mmc: sdhci-esdhc-imx: Remove unused variables

3f175a6e5 (mmc: sdhci-esdhc-imx: remove ESDHC_CD_GPIO handling from IO
accessory) introduced the following build warnings:

drivers/mmc/host/sdhci-esdhc-imx.c:149:30: warning: unused variable 'boarddata' [-Wunused-variable]
drivers/mmc/host/sdhci-esdhc-imx.c:181:30: warning: unused variable 'boarddata' [-Wunused-variable]

Remove the unused variables.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>