Provide default mixer configuration, so sound works by default. (#702)

Sound level is set to 80%, because of rumors that the speakers
could be damaged otherwise. Details in:
https://github.com/postmarketOS/pmbootstrap/pull/702

device/device-nokia-rx51/APKBUILD

 pkgname=device-nokia-rx51
 pkgver=1
-pkgrel=22
+pkgrel=23
 pkgdesc="Nokia N900"
 url="https://github.com/postmarketOS"
 arch="noarch"
@@ -19,6 +19,7 @@ source="
 	acpi.map
 	keymaps/rx51_us.map
 	pointercal
+	asound.state
 	$install
 "
 options="!check"
@@ -40,6 +41,8 @@ package() {
 		"$pkgdir"/etc/postmarketos-mkinitfs/hooks/00-${pkgname}-backlight.sh
 	install -D -m644 "$srcdir"/pointercal \
 		"$pkgdir"/etc/pointercal
+	install -D -m644 "$srcdir"/asound.state \
+		"$pkgdir"/var/lib/alsa/asound.state
 
 	# Udev rules
 	install -D -m644 "$srcdir"/90-touchscreen-dev.rules \
@@ -68,4 +71,5 @@ df5dcae9a32d04ba2fed8b4dbb8722f8d56d063a288dfbaeca37806bdbb8ba4de639b392859b9f24
 7761aec6e6e219245b006e7bdc1d19812e9c5915cf3e64bb3dd46bb4b5570c1715650b53a1fc1007cb814076b5d81be0a66ba7ebf06d9a1fa4e364725c3ee633  acpi.map
 c9ff8b5968fe94007e1139db5ae76f3ee6c214356bff297b9672276c6adb332ba2342b6ca54cf7992d6556f3c68a13ef49ae5e61abe86154935514034170e228  rx51_us.map
 143c21f0b18a016d37cb44178e9daea09f128a90769b48353c03c3f245cb9b1f7e773b9ccee084973fc78ddd7a18c2642e54888a85bda7c7daecddc9a8c62eff  pointercal
+e023df91295fe7e410e163747d17e5b92fe3c022ff076e286778b8334368f885603b8fda65671e4a7328766da7b2552ea4df1b1399df23e504a41a6655771142  asound.state
 a7ce458dd3c6d2b94639b59719ee972fe8c71781c3415f74f5340a4de1c8211853a07c29001ecbca832c471c288bed54b45c37fad05e088c197edc2bd7e7ce1b  device-nokia-rx51.post-install"