[Patch, ARM] Fix invalid immediate constant acceptance for carry-setting addw,subw.

[Nick Clifton]

Hi Tejas,

> Widening carry-setting thumb2 add and sub accepted invalid immediates
> which were flat 12-bit encoded. ADDS.W and SUBS.W's immediates have to
> be modified immediate constants(unlike addw and subw). Attached is a
> patch that adds this check and fixes it in gas. Regression tested on
> arm-none-eabi.

Thanks for reporting this problem and for supplying a patch.  I have now 
checked the patch into the mainline sources.

Cheers
   Nick