s390/ptdump: Add KMSAN page markers

Add KMSAN vmalloc metadata areas to
/sys/kernel/debug/kernel_page_tables. Example output:

    0x000003a95fff9000-0x000003a960000000        28K PTE I
    ---[ vmalloc Area End ]---
    ---[ Kmsan vmalloc Shadow Start ]---
    0x000003a960000000-0x000003a960010000        64K PTE RW NX
    [...]
    0x000003d3dfff9000-0x000003d3e0000000        28K PTE I
    ---[ Kmsan vmalloc Shadow End ]---
    ---[ Kmsan vmalloc Origins Start ]---
    0x000003d3e0000000-0x000003d3e0010000        64K PTE RW NX
    [...]
    0x000003fe5fff9000-0x000003fe60000000        28K PTE I
    ---[ Kmsan vmalloc Origins End ]---
    ---[ Kmsan Modules Shadow Start ]---
    0x000003fe60000000-0x000003fe60001000         4K PTE RW NX
    [...]
    0x000003fe60100000-0x000003fee0000000      2047M PMD I
    ---[ Kmsan Modules Shadow End ]---
    ---[ Kmsan Modules Origins Start ]---
    0x000003fee0000000-0x000003fee0001000         4K PTE RW NX
    [...]
    0x000003fee0100000-0x000003ff60000000      2047M PMD I
    ---[ Kmsan Modules Origins End ]---
    ---[ Modules Area Start ]---
    0x000003ff60000000-0x000003ff60001000         4K PTE RO X

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20240723124441.120044-3-iii@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>