mmc: omap_hsmmc: Add guards around omap_hsmmc_get_cfg()

We only call the function omap_hsmmc_get_cfg in the case of OMAP34XX or
when we have to iodelay recalibration.  Add guards for these checks as
clang will otherwise warn.

Cc: Peng Fan <peng.fan@nxp.com>
Cc: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>