[S390] Avoid compile warning.
[S390] Avoid compile warning.

arch/s390/mm/fault.c: In function `signal_return':
arch/s390/mm/fault.c:256: warning: unused variable `compat'

Signed-off-by: Heiko Carstens <8dcf0f69152f32f23184f83357a3731522e56b9c@de.ibm.com>

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