Fix various issues with zvols

When performing snapshot renames we could deadlock due to the locking
in zvol_rename_minors. In order to avoid this use the same workaround
as zvol_open in zvol_rename_minors.

Add missing zvol_rename_minors to dsl_dataset_promote_sync.

Protect against invalid index into zv_name in zvol_remove_minors.

Replace zvol_remove_minor calls with zvol_remove_minors to ensure
any potential children are also renamed.

Don't fail zvol_create_minors if zvol_create_minor returns EEXIST.

Restore the valid pool check in zfs_ioc_destroy_snaps to ensure we
don't call zvol_remove_minors when zfs_unmount_snap fails.

PR:		193803
MFC after:	1 week
Sponsored by:	Multiplay
Bump .Dd

Approved by:	kevlo
Allow vld and vst instructions to use the canonical form from ARM ARM when
including an alignment. Previously binutils would only allow instructions
in the form "vld1.64 {d0, d1}, [r0, :128]" where the final comma should
not be there, instead the above instruction should be
"vld1.64 {d0, d1}, [r0:128]".

This change duplicates the alignment code from within the function to
handle this case.