drivers: mmc: omap_hsmmc: fix build breakage

drivers: mmc: omap_hsmmc: fix build breakage

structure member 'cd_inverted' of omap_hsmmc_data
is available only when OMAP_HSMMC_USE_GPIO is
defined.

When CONFIG_DM_MMC is defined, but not
CONFIG_OMAP_GPIO, this will cause build breakage
in omap_hsmmc driver of the sort:

  CC      drivers/mmc/omap_hsmmc.o
../drivers/mmc/omap_hsmmc.c: In function 'omap_hsmmc_ofdata_to_platdata':
../drivers/mmc/omap_hsmmc.c:1763:6: error: 'struct omap_hsmmc_data' has no member named 'cd_inverted'
  priv->cd_inverted = fdtdec_get_bool(fdt, node, "cd-inverted");
      ^

Fix this by accessing cd_inverted only when
OMAP_HSMMC_USE_GPIO is defined.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>