android: util/format: fix generated sources rules

android: util/format: fix generated sources rules

Changes are necessary after commit 84ed2d098
("util/format: expose generated format packing functions through a header")
because script for format/u_format_pack.h has different commandline
compared to existing pattern

Generated sources rules are ported from meson

Fixes: 84ed2d098 ("util/format: expose generated format packing functions through a header")
Signed-off-by: Mauro Rossi <issor.oruam@gmail.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6319>