i965: Preserve the internal format of the dri image

i965: Preserve the internal format of the dri image

Since the OpenGLES API is strict about the internal format matching
the for many operations, we need to preserve it.

See _mesa_es3_error_check_format_and_type in
src/mesa/main/glformats.c.

Fixes ES2-CTS.gtf.GL2ExtensionTests.egl_image.egl_image

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96351
Reported-by: Mark Janes <mark.a.janes@intel.com>
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Cc: Kristian Høgsberg <krh@bitplanet.net>
Cc: Chad Versace <chad.versace@intel.com>
Cc: "12.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Chad Versace <chad.versace@intel.com>