esdhc/usdhc: Fix warning when CONFIG_SYS_FSL_ESDHC_USE_PIO is not set

In 71689776 we made calls to check_and_invalidate_dcache_range()
conditional on !CONFIG_SYS_FSL_ESDHC_USE_PIO.  Only define this function
in this case as well.

Signed-off-by: Tom Rini <trini@ti.com>

drivers/mmc/fsl_esdhc.c

@@ -246,6 +246,7 @@ static int esdhc_setup_data(struct mmc *mmc, struct mmc_data *data)
 	return 0;
 }
 
+#ifndef CONFIG_SYS_FSL_ESDHC_USE_PIO
 static void check_and_invalidate_dcache_range
 	(struct mmc_cmd *cmd,
 	 struct mmc_data *data) {
@@ -255,6 +256,8 @@ static void check_and_invalidate_dcache_range
 	unsigned end = start+size ;
 	invalidate_dcache_range(start, end);
 }
+#endif
+
 /*
  * Sends a command out on the bus.  Takes the mmc pointer,
  * a command pointer, and an optional data pointer.