KVM: s390: Refactor vcpu mem_op function

Remove code duplication with regards to the CHECK_ONLY flag.
Decrease the number of indents.
No functional change indented.

Suggested-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Link: https://lore.kernel.org/r/20230206164602.138068-12-scgl@linux.ibm.com


Message-Id: <20230206164602.138068-12-scgl@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>