broadcom/compiler: add driver_location_map at vs prog data

broadcom/compiler: add driver_location_map at vs prog data

This maps the nir shader data.location to its final
data.driver_location. In general we are using the driver location as
index (like vattr_sizes on the same struct), so having this map is
useful if what we have is the data.location, and we don't have
available the original nir shader.

v2: use memset instead of for loop, and nir_foreach_shader_in_variable
    instead of nir_foreach_variable_with_modes (Iago)

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9403>