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

[Przemyslaw Wirkus]

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

commit 5feaa09beca04312e51adc69766b0e4bfc181f99

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