android: radeonsi,ac: fix building error due to ac changes

android: radeonsi,ac: fix building error due to ac changes

Updates amd Makefile.sources and fixes the following building errors:

external/mesa/src/gallium/drivers/radeonsi/si_compute_prim_discard.c:338: error: undefined reference to 'ac_add_arg'
external/mesa/src/gallium/drivers/radeonsi/si_compute_prim_discard.c:340: error: undefined reference to 'ac_add_arg'
external/mesa/src/gallium/drivers/radeonsi/si_compute_prim_discard.c:341: error: undefined reference to 'ac_add_arg'
external/mesa/src/gallium/drivers/radeonsi/si_compute_prim_discard.c:342: error: undefined reference to 'ac_add_arg'

Fixes: 9885af3 ("ac: Add a shared interface between radv, radeonsi, LLVM and ACO")
Signed-off-by: Mauro Rossi <issor.oruam@gmail.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>