postmarketos-mkinitfs: add option to disable splash (MR 3305)

Add PMOS_NOSPLASH as a kernel command line option to disable
the splash screen to show the logs on the screen for debugging.

See https://wiki.postmarketos.org/wiki/Initramfs_development
on how to use it.

main/postmarketos-mkinitfs/APKBUILD

@@ -2,7 +2,7 @@
 # Co-Maintainer: Clayton Craft <clayton@craftyguy.net>
 pkgname=postmarketos-mkinitfs
 pkgver=1.4.1
-pkgrel=9
+pkgrel=10
 pkgdesc="Tool to generate initramfs images for postmarketOS"
 url="https://postmarketos.org"
 depends="
@@ -72,5 +72,5 @@ sha512sums="
 f827acb0a10c0e5c1631f1b712e91fde7eb4ade0f1174eb2ef1754018bf4518ea1ad3229fd335c25fb0c6fe46ae20890f5cf43e58c8143ae17b5ab9bb36f0199  postmarketos-mkinitfs-1.4.1.tar.gz
 20f110337113e8de8999cf2a064a93fea36821d5c216bfa4ba46ec1f83825638262b92fd7be29eee0a85a54a108b7315a96cbe30da8ae4419f54c2ed53bb08c7  00-default.modules
 ccdceaa710d97d6f57d8d66bfcbec448486d08083341712303f62123039f729229b88528308e411a308a2b90b81b60de89fe91143a6facbb11cbc9b4055eeaec  init.sh
-5edd28de09d82fad95d94eedeb37173683db2675390098942f9cb6caddc3669fd423208687aafc2228d74be70aabc672360e19f1ea100771cdf79c1df80c5e02  init_functions.sh
+cefebaf04f68c2787fad787458dd4533c507a15139e666d1985dba17dc55067c6246db14d174a5c302c2a9e077756b2ce6cccc59f7cabca11c2b1c44b6a2feb5  init_functions.sh
 "

main/postmarketos-mkinitfs/init_functions.sh

@@ -590,7 +590,10 @@ show_splash() {
 		echo "NOTE: Skipping framebuffer splashscreen (deviceinfo_no_framebuffer)"
 		return
 	fi
-
+	# Disable splash
+	if grep -q PMOS_NOSPLASH /proc/cmdline; then 
+         	return
+	fi
 	echo "IMG_ALIGN=CM" >>/tmp/fbsplash.cfg
 	gzip -c -d "$1" >/tmp/splash.ppm
 	fbsplash -s /tmp/splash.ppm -i /tmp/fbsplash.cfg