package/alsa-lib: bump to 1.2.5.1

package/alsa-lib: bump to 1.2.5.1

This version bump is needed prior to the introduction of alsa-plugins
1.2.5.

As part of this bump, we drop 0002-dlmisc-the-snd_plugin_dir_set.patch
which was an upstream backport, and we introduce
0002-fix-build-with-disable-ucm.patch to fix the build of alsa-lib
when UCM support is disabled. This patch is also backported from
upstream.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>