s390/mm: fix phys vs virt confusion in mark_kernel_pXd() functions family

[ Upstream commit 3784231b ]

Due to historical reasons mark_kernel_pXd() functions
misuse the notion of physical vs virtual addresses
difference.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Stable-dep-of: 44d93045 ("s390/cmma: fix detection of DAT pages")
Signed-off-by: Sasha Levin <sashal@kernel.org>