sata: ahsata: Fix resource leak

Fix coverity issue CID 3606684: Resource leak (RESOURCE_LEAK)
leaked_storage: Variable uc_priv going out of scope leaks the storage it points to

Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>