[XTENSA] Add missing a2 register restore in register spill routine
[XTENSA] Add missing a2 register restore in register spill routine

Register a2 is saved in depc but wasn't getting restored before
returning from _spill_registers when there weren't any registers
to spill. The mask to cut the top bit from the rotated WINDOWMASK
register was also one bit short.

Signed-off-by: CHris Zankel <711c73f64afdce07b7e38039a96d2224209e9a6c@zankel.net>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas