nvc0/nv50: support and enable EXT_memory_object*

./glcts --deqp-case=dEQP-EGL.functional.get_proc_address.extension.gl_ext_memory_object*

Test run totals:
  Passed:        3/3 (100.0%)
  Failed:        0/3 (0.0%)
  Not supported: 0/3 (0.0%)
  Warnings:      0/3 (0.0%)
  Waived:        0/3 (0.0%)

There is an issue with using that test as it reports Passed even without the EXT

Signed-off-by: Yusuf Khan <yusisamerican@gmail.com>