rpi-config: Upgrade to tip of tree to get GPU_MEM_1024

Document it in README

Signed-off-by: Khem Raj <raj.khem@gmail.com>

recipes-bsp/bootfiles/rpi-config_git.bb

@@ -7,7 +7,7 @@ LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384
 
 COMPATIBLE_MACHINE = "raspberrypi"
 
-SRCREV = "5d2ca5f9bcb1b239c051e20c05a233fd79cf09d5"
+SRCREV = "648ffc470824c43eb0d16c485f4c24816b32cd6f"
 SRC_URI = "git://github.com/Evilpaul/RPi-config.git;protocol=git;branch=master \
           "
 
@@ -54,6 +54,9 @@ do_deploy() {
     if [ -n "${GPU_MEM_512}" ]; then
         sed -i '/#gpu_mem_512/ c\gpu_mem_512=${GPU_MEM_512}' ${DEPLOYDIR}/bcm2835-bootfiles/config.txt
     fi
+    if [ -n "${GPU_MEM_1024}" ]; then
+        sed -i '/#gpu_mem_1024/ c\gpu_mem_1024=${GPU_MEM_1024}' ${DEPLOYDIR}/bcm2835-bootfiles/config.txt
+    fi
 
     # Video camera support
     if [ -n "${VIDEO_CAMERA}" ]; then