s390/vdso: add vdso support for coarse clocks

Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to
the 64-bit and 31-bit vdso.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --cc arch/s390/include/asm/vdso.h
Simple merge

diff --cc arch/s390/kernel/asm-offsets.c
Simple merge

diff --cc arch/s390/kernel/time.c
Simple merge

diff --cc arch/s390/kernel/vdso32/clock_getres.S
Simple merge

diff --cc arch/s390/kernel/vdso32/clock_gettime.S
Simple merge

diff --cc arch/s390/kernel/vdso64/clock_getres.S
Simple merge

diff --cc arch/s390/kernel/vdso64/clock_gettime.S
Simple merge