s390/boot: Use the full title of the manual for facility bits

s390/boot: Use the full title of the manual for facility bits

Also indicate the name of the section where facility bits are listed,
because the manual has a length of 2124 pages. The current version is
Fourteenth Edition (May, 2022) SA22-7832-13

Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: S390 ML <linux-s390@vger.kernel.org>
Signed-off-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250616163248.77951-1-xose.vazquez@gmail.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>