fix for memory leak in gc_hal_kernel_os.c

[aridet]

When the test (!((physical - Os->device->baseAddress) & 0x80000000)) returns true, the ref variable allocated line 4935 never get free'd and there is no more reference to it after that.

[otavio]

The change is lacking the Signed-off-by and the long commit log is larger than 80 cols. Apart from that it is fine for merge. Please make the adjustments and we can merge it.

[aridet]

Thanks, It should be fixed now (forced update).