David McFarland authored Oct 23, 2018 and Timothy Arceri committed Oct 26, 2018

After discussion with Timothy Arceri. disk_cache_get_function_identifier
was using only the first byte of the sha1 build-id.  Replace
disk_cache_get_function_identifier with implementation from
radv_get_build_id.  Instead of writing a uint32_t it now writes to a
mesa_sha1.  All drivers using disk_cache_get_function_identifier are
updated accordingly.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Fixes: 83ea8dd9 ("util: add disk_cache_get_function_identifier()")