[Patch][binutils][arm] Enable context sensitive .arch_extension

[Nick Clifton]

Hi Mihail,

> 2019-10-29  Mihail Ionescu  <mihail.ionescu@arm.com>
> 
> 	* config/tc-arm.c (selected_ctx_ext_table) New static variable.
> 	(arm_parse_arch): Set context sensitive extension table based on the
> 	chosen base architecture.
> 	(s_arm_arch_extension): Change to lookup extensions in the new context
> 	sensitive tables.
> 	* gas/testsuite/gas/arm/mve-ext.s: New.
> 	* gas/testsuite/gas/arm/mve-ext.d: New.
> 	* gas/testsuite/gas/arm/mvefp-ext.s: New.
> 	* gas/testsuite/gas/arm/mvefp-ext.d: New.

Approved and applied.

Cheers
  Nick