[PATCH][GAS] aarch64: Fix DSB instruction 'missing immediate expression' errors

[Nick Clifton]

Hi Przemyslaw,

> gas/ChangeLog:
> 2020-10-28  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>
> 
> 	* config/tc-aarch64.c (parse_operands): Check for C0-C15 value of DSB
> 	immediate string operand.
> 	* testsuite/gas/aarch64/system-4.d: Update test.
> 	* testsuite/gas/aarch64/system-4.s: Update test.

Approved - please apply.

Cheers
  Nick