android: anv/extensions: fix generated sources build

android: anv/extensions: fix generated sources build

Building rules are aligned to automake ones

The correct script to build anv_extensions.{c,h} is anv_extensions_gen.py
Generation rules for anv_extensions.c requires --out-c option
Generation rules for anv_extensions.h were missing
Necessary include paths are added to avoid following build errors:

cp: cannot stat '.../gen/STATIC_LIBRARIES/libmesa_vulkan_common_intermediates/vulkan/anv_extensions.c':
No such file or directory

In file included from external/mesa/src/intel/vulkan/anv_gem.c:32:
external/mesa/src/intel/vulkan/anv_private.h:75:10: fatal error: 'anv_extensions.h' file not found
         ^~~~~~~~~~~~~~~~~~
1 error generated.

In file included from external/mesa/src/intel/vulkan/anv_batch_chain.c:30:
external/mesa/src/intel/vulkan/anv_private.h:75:10: fatal error: 'anv_extensions.h' file not found
         ^~~~~~~~~~~~~~~~~~
1 error generated.

Fixes: dd088d4bec7 ("anv/extensions: Generate a header file with extension tables")
Cc: "18.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>