Temporary fix for alsa-lib breakage with --disable-pcm

The current version of alsa-lib (1.0.22) does not build when
--disable-pcm is used at configure time. I've reported the issue at
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=4913.

In the mean time, we can prevent the user from not selecting PCM
support by using the following patch.

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

package/multimedia/alsa-lib/Config.in

@@ -1,5 +1,9 @@
 config BR2_PACKAGE_ALSA_LIB
 	bool "alsa-lib"
+	# Temporary until
+	# https://bugtrack.alsa-project.org/alsa-bug/view.php?id=4913
+	# is fixed
+	select BR2_PACKAGE_ALSA_LIB_PCM
 	help
 	  The Advanced Linux Sound Architecture (ALSA) provides audio and MIDI
 	  functionality to the Linux operating system.