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/dma/apbh_dma.c b/drivers/dma/apbh_dma.c
index 38eff4f..ca5a32f 100644
--- a/drivers/dma/apbh_dma.c
+++ b/drivers/dma/apbh_dma.c
@@ -512,7 +512,7 @@
 	if (ret)
 		return ret;
 
-	if (mx28_wait_mask_set(&apbh_regs->hw_apbh_ctrl1_reg,
+	if (mxs_wait_mask_set(&apbh_regs->hw_apbh_ctrl1_reg,
 				1 << chan, timeout)) {
 		ret = -ETIMEDOUT;
 		mxs_dma_reset(chan);
@@ -557,7 +557,7 @@
 	struct mxs_apbh_regs *apbh_regs =
 		(struct mxs_apbh_regs *)MXS_APBH_BASE;
 
-	mx28_reset_block(&apbh_regs->hw_apbh_ctrl0_reg);
+	mxs_reset_block(&apbh_regs->hw_apbh_ctrl0_reg);
 
 #ifdef CONFIG_APBH_DMA_BURST8
 	writel(APBH_CTRL0_AHB_BURST8_EN,