Build: Make incompatible-pointer-types warning

On GCC14, incompatible-pointer-types has been upgraded from warning to
an error, which causes build failures, particularly in the tests. Add a
command line argument to the compiler to revert back to the GCC13
behaviour and treat it as a warning instead.

Note that imcompatible-pointer-types is a warning that should definitely
be fixed as can lead to unexpected behaviour, but for now this at least
lets us build with GCC14.

Change-Id: I8c985121a9cba094eb923ca043066b64ee3bc35a
Signed-off-by: Jackson Cooper-Driver <jackson.cooper-driver@arm.com>
diff --git a/toolchain_GNUARM.cmake b/toolchain_GNUARM.cmake
index cec82f9..e727b0f 100644
--- a/toolchain_GNUARM.cmake
+++ b/toolchain_GNUARM.cmake
@@ -54,6 +54,7 @@
     -Wno-format
     -Wno-unused-but-set-variable
     -Wnull-dereference
+    -Wno-error=incompatible-pointer-types
     -c
     -fdata-sections
     -ffunction-sections