drm_hwcomposer: Remove unused ResourceManager::gralloc_ field

It was added with initial ResourceManager implementation and was
never used.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/drm/ResourceManager.cpp b/drm/ResourceManager.cpp
index 224e709..76a36e1 100644
--- a/drm/ResourceManager.cpp
+++ b/drm/ResourceManager.cpp
@@ -29,7 +29,7 @@
 
 namespace android {
 
-ResourceManager::ResourceManager() : num_displays_(0), gralloc_(nullptr) {
+ResourceManager::ResourceManager() : num_displays_(0) {
 }
 
 int ResourceManager::Init() {
@@ -70,8 +70,7 @@
     return -EINVAL;
   }
 
-  return hw_get_module(GRALLOC_HARDWARE_MODULE_ID,
-                       (const hw_module_t **)&gralloc_);
+  return 0;
 }
 
 int ResourceManager::AddDrmDevice(const std::string &path) {
@@ -126,8 +125,4 @@
   }
   return nullptr;
 }
-
-const gralloc_module_t *ResourceManager::gralloc() {
-  return gralloc_;
-}
 }  // namespace android