radeonsi: Don't force dcc disable for loads

radeonsi: Don't force dcc disable for loads

When e9d935ed0e2 added force_dcc_off(), we forced it off for any
preloaded image descriptor which had stores associated with them, since
the same preloaded descriptors were used for loads and stores. However,
when the preloading was removed in 16be87c9042, the existing logic was
kept despite it not being necessary anymore. The comment above
force_dcc_off() only mentions stores, so only force DCC off for stores.

Cc: Nicolai Hähnle <nicolai.haehnle@amd.com>
Cc: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>