mmc: fsl_esdhc: correct type of wp_enable

The type should be int, not u8. cfg->wp_enable will finally be
assigned to priv->wp_enable whose type is int.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/include/fsl_esdhc.h b/include/fsl_esdhc.h
index e15d3ae..5550e00 100644
--- a/include/fsl_esdhc.h
+++ b/include/fsl_esdhc.h
@@ -177,7 +177,7 @@
 	phys_addr_t esdhc_base;
 	u32	sdhc_clk;
 	u8	max_bus_width;
-	u8	wp_enable;
+	int	wp_enable;
 	struct mmc_config cfg;
 };