monitor: Fix build errors due to unaligned memory access

monitor: Fix build errors due to unaligned memory access

This fix following compilation errors on ARM.

  CC     monitor/hcidump.o
monitor/hcidump.c: In function ‘device_callback’:
monitor/hcidump.c:147:11: error: cast increases required alignment of
	target type [-Werror=cast-align]
monitor/hcidump.c:150:10: error: cast increases required alignment of
	target type [-Werror=cast-align]
monitor/hcidump.c: In function ‘stack_internal_callback’:
monitor/hcidump.c:348:9: error: cast increases required alignment of
	target type [-Werror=cast-align]
cc1: all warnings being treated as errors
make[1]: *** [monitor/hcidump.o] Error 1

  CC     monitor/control.o
monitor/control.c: In function ‘data_callback’:
monitor/control.c:584:10: error: cast increases required alignment of
	target type [-Werror=cast-align]
cc1: all warnings being treated as errors
make[1]: *** [monitor/control.o] Error 1