Destination slot is occupied for cap transfer

[Liblor]

https://github.com/Liblor/advanced_operating_systems_2020/tree/bug/destination-slot-occupied

System counter frequency is 8000000Hz.
Timeslice interrupt every 640000 ticks (80ms).
kernel 0: ARMv8-A: Setting coreboot spawn handler
kernel 0: ARMv8-A: Calling arm_kernel_startup
kernel 0: ARMv8-A: Doing BSP related bootup
start_free_ram = 0x80201000
kernel 0: ARMv8-A: spawning 'armv8/sbin/init' on BSP core
kernel 0: ARMv8-A: spawn_init_common armv8/sbin/init
spawn module: armv8/sbin/init
kernel 0: init page tables: l0=0xffff000080520000, l1=0xffff000080521000, l2=0xffff000080522000, l3=0xffff000080532000
load_init_image 0xffff0000fbfdd000 0008451f
kernel 0: ARMv8-A: init loaded with entry=0x400974 and GOT=0x45ad18
kernel 0: ARMv8-A: Calling dispatch from arm_kernel_startup, entry point 0x400974
init.0.0: initializing static heap
init.0.0: init: on core 0, invoked as:init.0.0: Added 1958 MB of physical memory.
init.0.0: processserver_init()
init.0.0: name is: /armv8/sbin/dummy
kernel 0: ARMv8-A: Timer interrupt received!
dummy.0.0: initializing static heap
init.0.0: name is: /armv8/sbin/dummy
dummy.0.0: initializing static heap
dummy.0.0: A transient error occured 10 times, retries exceeded
dummy.0.0: lmp_chan_send0() failed: Destination slot is occupied for cap transfer
dummy.0.0: Error while setting up channel for init
dummy.0.0: aos_rpc_lmp_setup_channel() failed
init.0.0: name is: /armv8/sbin/dummy

[abertschi]

Discovered in #90