ASoC: Intel: remove second duplicated assignment to pointer 'res'

The second assignment to res is identical to the previous assignment
so it is redundant and can be removed.

Cleans up clang warning:
sound/soc/intel/skylake/skl-topology.c:191:25: warning: Value stored to
'res' during its initialization is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/intel/skylake/skl-topology.c

@@ -190,7 +190,6 @@ skl_tplg_free_pipe_mcps(struct skl *skl, struct skl_module_cfg *mconfig)
 	u8 res_idx = mconfig->res_idx;
 	struct skl_module_res *res = &mconfig->module->resources[res_idx];
 
-	res = &mconfig->module->resources[res_idx];
 	skl->resource.mcps -= res->cps;
 }