radeonsi: handle imported textures with DCC robustly

now you can hack the driver to enable DCC for displayable textures and
Glamor that doesn't enable that by default won't crash anymore.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
index fcf4928..46c45ea 100644
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -4625,7 +4625,7 @@
 	    md->metadata[0] != 0 &&
 	    md->metadata[1] == si_get_bo_metadata_word1(rscreen) &&
 	    G_008F28_COMPRESSION_EN(desc[6])) {
-		assert(rtex->dcc_offset == ((uint64_t)desc[7] << 8));
+		rtex->dcc_offset = (uint64_t)desc[7] << 8;
 		return;
 	}