drm_hwcomposer: clang-tidy: enable cppcoreguidelines-* checks

Our code isn't ready for the following checks therefore keep disabled
-cppcoreguidelines-pro-bounds-array-to-pointer-decay
-cppcoreguidelines-pro-bounds-constant-array-index
-cppcoreguidelines-pro-bounds-pointer-arithmetic
-cppcoreguidelines-pro-type-cstyle-cast
-cppcoreguidelines-pro-type-vararg
-cppcoreguidelines-avoid-magic-numbers
-cppcoreguidelines-macro-usage
-cppcoreguidelines-avoid-c-arrays

+ fixed existing tidy warnings for these checks.

Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
diff --git a/utils/hwcutils.cpp b/utils/hwcutils.cpp
index 9a49c41..35c9fb6 100644
--- a/utils/hwcutils.cpp
+++ b/utils/hwcutils.cpp
@@ -72,13 +72,12 @@
 }
 
 int DrmHwcNativeHandle::CopyBufferHandle(buffer_handle_t handle) {
-  native_handle_t *handle_copy;
+  native_handle_t *handle_copy = nullptr;
   GraphicBufferMapper &gm(GraphicBufferMapper::get());
-  int ret;
+  int ret = 0;
 
   ret = gm.getGrallocMapper().importBuffer(handle,
-                                           const_cast<buffer_handle_t *>(
-                                               &handle_copy));
+                                           (buffer_handle_t *)&handle_copy);
 
   if (ret) {
     ALOGE("Failed to import buffer handle %d", ret);