mmc: sdhci-esdhc-imx: remove unused is_imx6q_usdhc

The is_imx6q_usdhc() function is unused:

drivers/mmc/host/sdhci-esdhc-imx.c:343:19: warning: unused function 'is_imx6q_usdhc'

Reported-by: kernel test robot <[e-mail]>
Fixes: f47c4bbfa283 ("mmc: sdhci-esdhc-imx: create struct esdhc_soc_data")
Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Haibo Chen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/host/sdhci-esdhc-imx.c

···
 	return data->socdata == &esdhc_imx53_data;
 }
 
-static inline int is_imx6q_usdhc(struct pltfm_imx_data *data)
-{
-	return data->socdata == &usdhc_imx6q_data;
-}
-
 static inline int esdhc_is_usdhc(struct pltfm_imx_data *data)
 {
 	return !!(data->socdata->flags & ESDHC_FLAG_USDHC);