templates: raspberrypi: lower GPU_MEM

GPU_MEM is not used by vc4graphics.

See commit for a more detailed description.

Signed-off-by: Mirza Krak <mirza.krak@northern.tech>

Author: mirzak

gdp-src-build/conf/templates/raspberrypi.local.inc

@@ -1,6 +1,12 @@
 include local.inc
 
-GPU_MEM = "128"
+# vc4grahpics do not use GPU_MEM, instead it uses the CMA memory, allocating
+# a high number of GPU_MEM does seem to eat memory from CMA causing OOM errors.
+#
+# Ultimatly we would like to set this to 0, but it does seem to need a small
+# amount otherwise the system will not boot. Fails at first stage already,
+# loading the Linux kernel.
+GPU_MEM = "16"
 
 MACHINE_FEATURES_append = " vc4graphics"