st/mesa: add missing ETC2 entries to format_map
st/mesa: add missing ETC2 entries to format_map

Noticed by Ilia when I was trying to figure out why some app was failing
to use ETC2.

Signed-off-by: Rob Clark <6f78cdb10adbe0a7fbbf4098125a51f401c77a5f@freedesktop.org>
Reviewed-by: Ilia Mirkin <bcbbb7aa705ec3a5fc5824c01a845186c3d62fca@alum.mit.edu>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler