glsl: Fix yylloc.source propagation in YYLLOC_DEFAULT

glsl: Fix yylloc.source propagation in YYLLOC_DEFAULT

Currently, it's always initialized to 0, but we should take the value from
the grouping passed to the macro. This way parser will have the full
location info, and errors originating from it will show the correct
source file number.

Fixes: a0cfe8c4 ("glsl: Fix missing initialization of yylloc.source")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9229
Signed-off-by: Sviatoslav Peleshko <sviatoslav.peleshko@globallogic.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23966>