build(imx93): add build configs for imx93

Add build configs for i.MX93.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: I518b42151bbc440a3b3237bf98f5162a2cb462d0
diff --git a/tf_config/imx93-default b/tf_config/imx93-default
new file mode 100644
index 0000000..0db5f86
--- /dev/null
+++ b/tf_config/imx93-default
@@ -0,0 +1,2 @@
+CROSS_COMPILE=aarch64-none-elf-
+PLAT=imx93