SWDEV-273235 - Find UGL headers based on AMD_DRIVERS_PATH
SWDEV-273235 - Find UGL headers based on AMD_DRIVERS_PATH

All KMD/asic_reg/UGL headers are located under the drivers folder. No
need for the AMD_UGL_PATH variable as it essentially is
${AMD_DRIVERS_PATH}/ugl.

Change-Id: I070d737d50f2096493b3e75ef9b9e824cb19d048

ROCm-Developer-Tools/ROCclr,ROCm-Developer-Tools/ROCclr