This patch fixes an uninitialized memory issue that can under certain
circumstances turn an error into a warning because non_fatal was not initialised
in all cases.

Verified using valgrind.

gas/config/tc-aarch64.c

	PR binutils/21446
	* tc-aarch64.c (record_operand_error, record_operand_error_with_data):
	  Initialize non_fatal.