xfs: fix log reservation overflows when allocating large rt extents

xfs: fix log reservation overflows when allocating large rt extents

Omar Sandoval reported that a 4G fallocate on the realtime device causes
filesystem shutdowns due to a log reservation overflow that happens when
we log the rtbitmap updates.  Factor rtbitmap/rtsummary updates into the
the tr_write and tr_itruncate log reservation calculation.

"The following reproducer results in a transaction log overrun warning
for me:

    mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb
    mount -o rtdev=/dev/vdc /dev/vdb /mnt
    fallocate -l 4G /mnt/foo

Reported-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>