meta: Fix ClearTexture with GL_DEPTH_COMPONENT.

We only handled unpacking for GL_DEPTH_STENCIL formats.

Cemu was hitting _mesa_problem() for an unsupported format in
_mesa_unpack_float_32_uint_24_8_depth_stencil_row(), because the
format was depth-only, rather than depth-stencil.

Cc: "13.0 12.0" <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94739
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103966


Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
(cherry picked from commit 8705ed13)