s390/perf_events: compile only for CONFIG_64BIT
s390/perf_events: compile only for CONFIG_64BIT

The whole hardware support is only available in zArch mode.
Fixes also this compile warning:

arch/s390/kernel/perf_cpum_cf.c: In function ‘cpumf_pmu_init’:
arch/s390/kernel/perf_cpum_cf.c:670:2: warning: left shift count >= width of type [enabled by default]

Signed-off-by: Heiko Carstens <8dcf0f69152f32f23184f83357a3731522e56b9c@de.ibm.com>
Signed-off-by: Martin Schwidefsky <52616596d8f5df0d597e85ab515377f92f939c68@de.ibm.com>

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