mxs: Convert sys_proto.h prefixes to 'mxs'

The sys_proto.h functions (except the boot modes) are compatible with
i.MX233 and i.MX28 so we use 'mxs' prefix for its methods.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
diff --git a/drivers/mmc/mxsmmc.c b/drivers/mmc/mxsmmc.c
index 018939f..9a98c6b 100644
--- a/drivers/mmc/mxsmmc.c
+++ b/drivers/mmc/mxsmmc.c
@@ -336,7 +336,7 @@
 	struct mxs_ssp_regs *ssp_regs = priv->regs;
 
 	/* Reset SSP */
-	mx28_reset_block(&ssp_regs->hw_ssp_ctrl0_reg);
+	mxs_reset_block(&ssp_regs->hw_ssp_ctrl0_reg);
 
 	/* 8 bits word length in MMC mode */
 	clrsetbits_le32(&ssp_regs->hw_ssp_ctrl1,