ext4: fix remount with 'abort' option

ext4: fix remount with 'abort' option

After commit 6e47a3cc68fc ("ext4: get rid of super block and sbi from
handle_mount_ops()") the 'abort' options stopped working. This is
because we're using ctx_set_mount_flags() helper that's expecting an
argument with the appropriate bit set, but instead got
EXT4_MF_FS_ABORTED which is a bit position. ext4_set_mount_flag() is
using set_bit() while ctx_set_mount_flags() was using bitwise OR.

Create a separate helper ctx_set_mount_flag() to handle setting the
mount_flags correctly.

While we're at it clean up the EXT4_SET_CTX macros so that we're only
creating helpers that we actually use to avoid warnings.

Fixes: 6e47a3cc68fc ("ext4: get rid of super block and sbi from handle_mount_ops()")
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Cc: Ye Bin <yebin10@huawei.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Tested-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Link: https://lore.kernel.org/r/20220201131345.77591-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>