sdm: Provide best mode support for hdmi drm device

DRM userconfig should be in w:h:fps:format.
FB userconfig should be vic mode.

1. Fix existing bugs in loop traversing to iterate through the mode list.
2. Fix best mode selection logic of preferring width over height.

CRs-Fixed: 2078126
Change-Id: Ia4d1621d11f5fcf17b33cfede56222e30bfd7032
diff --git a/sdm/include/utils/debug.h b/sdm/include/utils/debug.h
index 2bd6a5a..0b40e7b 100644
--- a/sdm/include/utils/debug.h
+++ b/sdm/include/utils/debug.h
@@ -63,7 +63,7 @@
   }
   static inline DebugHandler* Get() { return debug_.debug_handler_; }
   static int GetSimulationFlag();
-  static int GetHDMIResolution();
+  static bool GetExternalResolution(char *val);
   static void GetIdleTimeoutMs(uint32_t *active_ms, uint32_t *inactive_ms);
   static int GetBootAnimLayerCount();
   static bool IsRotatorDownScaleDisabled();