CHROMIUM: Add #line to arm_mpu_v7_internal.h

Work around coreboot GCC preprocessor bug.

BUG=b:272518464
TEST=BOARD=brya; zmake build --coverage $BOARD &&
./util/find_non_exec_lines.py build/zephyr/$BOARD/output/zephyr.info

Change-Id: I77c472a0de01674c78a83fda0b746a5b287df756
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5899495
Tested-by: Jeremy Bettis <jbettis@chromium.org>
Reviewed-by: Tomasz Michalec <tmichalec@google.com>
Commit-Queue: Jeremy Bettis <jbettis@chromium.org>

arch/arm/core/mpu/arm_mpu_v7_internal.h

@@ -14,7 +14,7 @@
 
 #define LOG_LEVEL CONFIG_MPU_LOG_LEVEL
 #include <zephyr/logging/log.h>
-
+#line 18
 /* Global MPU configuration at system initialization. */
 static void mpu_init(void)
 {