DM: Fix device mapper topology stacking
DM: Fix device mapper topology stacking

Make DM use bdev_stack_limits() function so that partition offsets get
taken into account when calculating alignment.  Clarify stacking
warnings.

Also remove obsolete clearing of final alignment_offset and misalignment
flag.

Signed-off-by: Martin K. Petersen <0384aaef27f06874adbdb09a807bb339f4aff9fd@oracle.com>
Signed-off-by: Mike Snitzer <85e533f2e78486213c4d69f71462342ec0c62734@redhat.com>
Cc: Alasdair G. Kergon <620085386a2c64ec2f1d43bef997c15003f13da2@redhat.com>
Signed-off-by: Jens Axboe <165ab144a3ccfd9429d5c6466b275f24fafdb114@oracle.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas