psplash: Fix build with GCC 15

Pull in upstream changes for fix the build with gcc 15 and README tweaks.

(From OE-Core rev: 0ba624f30d482c0c7d86202d46abdab9d148c9b0)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/psplash/psplash_git.bb

@@ -6,7 +6,7 @@ LICENSE = "GPL-2.0-or-later"
 LIC_FILES_CHKSUM = "file://psplash.h;beginline=1;endline=8;md5=8f232c1e95929eacab37f00900580224"
 DEPENDS = "gdk-pixbuf-native"
 
-SRCREV = "5a32cf6392c784a7ae1983a354cf07b024625cd2"
+SRCREV = "1f64c654129fdb6a1b75d8c16e3bcdd986468083"
 PV = "0.1+git"
 
 SRC_URI = "git://git.yoctoproject.org/${BPN};branch=master;protocol=https \