Remove HIDL_GENERATED from things written by hand.

find . -name "*.h" -exec sed -i 's/HIDL_GENERATED_\(.*\)_H_/\U\1_H/g' {}
+

They now match what would be generated by -Lc++-impl. This prevents
confusion over whether or not the files are autogenerated.

Change-Id: I4aa89a39907024aa9525df71ff3715979f431357
Similar commit: https://android-review.googlesource.com/#/c/305996/
Test: pass