android: ac: add ac_nir_lower_ngg.c to Makefile.sources

android: ac: add ac_nir_lower_ngg.c to Makefile.sources

Fixes the following building errors:

external/mesa/src/amd/vulkan/radv_shader.c:868: error: undefined reference to 'ac_nir_lower_ngg_gs'
external/mesa/src/amd/vulkan/radv_shader.c:851: error: undefined reference to 'ac_nir_lower_ngg_nogs'
external/mesa/src/amd/compiler/aco_interface.cpp:155: error: undefined reference to 'aco::optimize_postRA(aco::Program*)'

Fixes: 3d589b8b464 ("ac: Add new NIR pass to lower NGG VS/TES.")
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11177>