selftests: kvm: s390: Define page sizes in shared header

selftests: kvm: s390: Define page sizes in shared header

Multiple test cases need page size and shift definitions.
By moving the definitions to a single architecture specific header we
limit the repetition.

Make use of PAGE_SIZE, PAGE_SHIFT and PAGE_MASK defines in existing
code.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20240807154512.316936-2-schlameuss@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20240807154512.316936-2-schlameuss@linux.ibm.com>