platform: msm8994: Fix compilation warnings in platform files

Add clk related functions to platform specific clk header file
and fix multiple macro definitions to avoid compilation warnings.
It is done in an effort to enable WERROR.

Change-Id: I78e9a63b32302ddda0a840e51090a92ca5c062dc
diff --git a/platform/msm8994/include/platform/iomap.h b/platform/msm8994/include/platform/iomap.h
index 1774aa5..ab64e78 100644
--- a/platform/msm8994/include/platform/iomap.h
+++ b/platform/msm8994/include/platform/iomap.h
@@ -305,6 +305,10 @@
 #undef MDP_INTF_1_TIMING_ENGINE_EN
 #endif
 #define MDP_INTF_1_TIMING_ENGINE_EN             REG_MDP(0x6b800)
+
+#ifdef MDP_INTF_2_TIMING_ENGINE_EN
+#undef MDP_INTF_2_TIMING_ENGINE_EN
+#endif
 #define MDP_INTF_2_TIMING_ENGINE_EN             REG_MDP(0x6C000)
 
 #ifdef MDP_CTL_0_BASE