[PATCH][GAS][AArch64] Define BRBE system registers

[Przemyslaw Wirkus]

> Hi Przemyslaw,
> 
> > OK for master branch?
> 
> Approved - please apply.

commit 6278c6a66379c40d2d91107a2101408ec4ca0673

> > gas/ChangeLog:
> > 2020-10-08  Przemyslaw Wirkus  <mailto:przemyslaw.wirkus@arm.com>
> >
> > 	* NEWS: Docs update.
> > 	* testsuite/gas/aarch64/brbe-invalid.d: New test.
> > 	* testsuite/gas/aarch64/brbe-invalid.l: New test.
> > 	* testsuite/gas/aarch64/brbe-invalid.s: New test.
> > 	* testsuite/gas/aarch64/brbe.d: New test.
> > 	* testsuite/gas/aarch64/brbe.s: New test.
> >
> > opcodes/ChangeLog:
> > 2020-10-08  Przemyslaw Wirkus  <mailto:przemyslaw.wirkus@arm.com>
> >
> > 	* aarch64-opc.c: Add BRBE system registers.
> 
> Cheers
>   Nick
>