st/dri: Support 24bit formats in dri2_allocate_buffer

Prior commit 576161289df68eedade591fbca4013329c9e5ded,
the parameter format was bpp, thus both 24bit and 32bit formats were
requested with format set to 32. Handle 24bit seperately now.

Fixes RGBX formats in wayland platform for egl_dri2 (EGL_ALPHA_SIZE=0).

Note: This is a candidate for the 8.0 branch.
1 file changed