Build warnings [-Wpointer-sign] with LLVM/icx (bluetooth_ipsp)

[nashif]

Reported by Sharron LIU:

Test case with build warnings raised from LLVM/icx: samples_bluetooth_ipsp

/home/sharron/workspace/views/iot/zephyr/subsys/net/ip/net_core.c:544:34: warning:
      passing 'char [1200]' to parameter of type 'unsigned char *' converts
      between pointers to integer types with different sign [-Wpointer-sign]
                net_analyze_stack("RX thread", rx_stack, sizeof(rx_stack));
                                               ^~~~~~~~
/home/sharron/workspace/views/iot/zephyr/include/net/net_core.h:182:25: note:
      passing argument to parameter 'stack' here
                                     unsigned char *stack,
                                                    ^
1 warning generated.
/home/sharron/workspace/views/iot/zephyr/subsys/net/ip/net_if.c:127:34: warning:
      passing 'char [1200]' to parameter of type 'unsigned char *' converts
      between pointers to integer types with different sign [-Wpointer-sign]
                net_analyze_stack("TX thread", iface->tx_stack,
                                               ^~~~~~~~~~~~~~~
/home/sharron/workspace/views/iot/zephyr/include/net/net_core.h:182:25: note:
      passing argument to parameter 'stack' here
                                     unsigned char *stack,
                                                    ^
1 warning generated.
/home/sharron/workspace/views/iot/zephyr/subsys/net/ip/net_shell.c:137:18: warning:
      passing 'char [1200]' to parameter of type 'unsigned char *' converts
      between pointers to integer types with different sign [-Wpointer-sign]
        tx_stack(iface, iface->tx_stack, CONFIG_NET_TX_STACK_SIZE);
                        ^~~~~~~~~~~~~~~
/home/sharron/workspace/views/iot/zephyr/subsys/net/ip/net_shell.c:99:59: note:
      passing argument to parameter 'stack' here
static void tx_stack(struct net_if *iface, unsigned char *stack,
                                                          ^
/home/sharron/workspace/views/iot/zephyr/subsys/net/ip/net_shell.c:783:32: warning:
      passing 'char *' to parameter of type 'unsigned char *' converts between
      pointers to integer types with different sign [-Wpointer-sign]
                net_analyze_stack_get_values(info->stack, info->size,
                                             ^~~~~~~~~~~
/home/sharron/workspace/views/iot/zephyr/include/net/net_core.h:136:64: note:
      passing argument to parameter 'stack' here
static inline void net_analyze_stack_get_values(unsigned char *stack,
                                                               ^
2 warnings generated.

how-to-reproduce:

source zephyr-env.sh

export ZEPHYR_GCC_VARIANT=issm

cd samples/bluetooth/ipsp

make pristine

make BOARD=arduino_101 CC=icx

(Imported from Jira ZEP-1881)

[nashif]

by Sharron LIU:

Andrei Laperie , could you assign this? Warnings raised from "net_core" "net_if", "net_shell". Thanks.

[nashif]

References GH-1705