Change return type of raw_bkpt_type_to_arm_hwbp_type

Change return type of raw_bkpt_type_to_arm_hwbp_type

Fixes:

/home/simark/src/binutils-gdb/gdb/gdbserver/linux-arm-low.c: In function ‘int arm_linux_hw_point_initialize(raw_bkpt_type, CORE_ADDR, int, arm_linux_hw_breakpoint*)’:
/home/simark/src/binutils-gdb/gdb/gdbserver/linux-arm-low.c:459:55: error: invalid conversion from ‘int’ to ‘arm_hwbp_type’ [-fpermissive]
   hwbp_type = raw_bkpt_type_to_arm_hwbp_type (raw_type);
                                                       ^

gdb/gdbserver/ChangeLog:

		* linux-arm-low.c (raw_bkpt_type_to_arm_hwbp_type):
		Change return type to arm_hwbp_type.