ANDROID: Make KMI_SYMBOL_LIST_STRICT_MODE overrideable

For development purposes, it can be useful to disable strict symbol list
checking, but this value is currently always being set to 1 in the arm64
config. Allow for this value to be overridden, with the default of being
enabled.

Bug: 184667897
Signed-off-by: J. Avila <elavila@google.com>
Change-Id: Ie6295a2cb9d89b30e2242e2d55639a2c4882a897
diff --git a/build.config.gki.aarch64 b/build.config.gki.aarch64
index 7630995..e8c0aef 100644
--- a/build.config.gki.aarch64
+++ b/build.config.gki.aarch64
@@ -22,6 +22,6 @@
 "
 
 TRIM_NONLISTED_KMI=1
-KMI_SYMBOL_LIST_STRICT_MODE=1
+KMI_SYMBOL_LIST_STRICT_MODE=${KMI_SYMBOL_LIST_STRICT_MODE:-1}
 MODULES_ORDER=android/gki_aarch64_modules
 KMI_ENFORCED=1