android: try to load gallium_dri.so directly

android: try to load gallium_dri.so directly

This avoids needing hardlinks between all of the DRI driver .so names,
since we're the only loader on the system.

v2: Add early exit on success (like previous block) and log message on
    failure.

Signed-off-by: Chih-Wei Huang <cwhuang@linux.org.tw>
Reviewed-by: Eric Anholt <eric@anholt.net>