arch: arm: Fix compilation warnings

Fix comilation warnings in an effort to turn on WERROR.

Change-Id: I1becc0d2d3e05fb0dff1361157cd0a83395c137e
diff --git a/arch/arm/include/arch/arm.h b/arch/arm/include/arch/arm.h
index a14bf9c..e056628 100644
--- a/arch/arm/include/arch/arm.h
+++ b/arch/arm/include/arch/arm.h
@@ -87,6 +87,8 @@
 void arm_write_dacr(uint32_t val);
 void arm_invalidate_tlb(void);
 
+void dump_fault_frame(struct arm_fault_frame *frame);
+
 #if defined(__cplusplus)
 }
 #endif