package/psplash: add support for fullscreen config option

Add support for a psplash configure option:
  --enable-img-fullscreen, via BR2_PACKAGE_PSPLASH_FULL_SCREEN

The Buildroot option will default to 'n' to be compatible with
the previous behaviour, as it was disabled by default in psplash.

Note: the --enable-img-fullscreen configure option has been supported
in psplash since upstream commit:
https://git.yoctoproject.org/psplash/commit/?id=773a3977d255e8f59a741ad6ce37c4d40f1feaa1

Signed-off-by: Olivier Benjamin <olivier.benjamin@bootlin.com>
[Julien: add note in commit log about upstream support]
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/psplash/Config.in

@@ -47,6 +47,12 @@ config BR2_PACKAGE_PSPLASH_STARTUP_MSG
 	help
 	  Enable text banner output on startup.
 
+config BR2_PACKAGE_PSPLASH_FULL_SCREEN
+	bool "use fullscreen mode"
+	default n
+	help
+	  Enable displaying the psplash image in fullscreen mode.
+
 endif
 
 comment "psplash needs a toolchain w/ wchar"

package/psplash/psplash.mk

@@ -31,6 +31,12 @@ else
 PSPLASH_CONF_OPTS += --disable-startup-msg
 endif
 
+ifeq ($(BR2_PACKAGE_PSPLASH_FULL_SCREEN),y)
+PSPLASH_CONF_OPTS += --enable-img-fullscreen
+else
+PSPLASH_CONF_OPTS += --disable-img-fullscreen
+endif
+
 PSPLASH_IMAGE = $(call qstrip,$(BR2_PACKAGE_PSPLASH_IMAGE))
 
 ifneq ($(PSPLASH_IMAGE),)