i965: do_blit_drawpixels: decode array formats

i965: do_blit_drawpixels: decode array formats

Correct a regression introduced by commit 922c0c9fd526 by converting "array
format", if received from _mesa_format_from_format_and_type, to mesa_format.

References: https://bugs.freedesktop.org/show_bug.cgi?id=90839
Signed-off-by: Alexander Monakov <amonakov@gmail.com>
Tested-by: AnAkkk <anakin.cs@gmail.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Cc: mesa-stable@lists.freedesktop.org