gdb: fix indentation in arm_record_data_proc_misc_ld_str

The scopes under this "if" are over-indented, fix that.

gdb/ChangeLog:

	* arm-tdep.c (arm_record_data_proc_misc_ld_str): Fix
	indentation.

Change-Id: I84a551793207ca95d0bc4f122e336555c8179c0e