mmc: msm_sdcc: add BUG_ON() checks for data buffer sg list

For data transfer requests, make sure that sg list is
not NULL and length of sg list is not zero.

Change-Id: I0d9c317a9fc2660e8495eeeb9c3d806c68f074d2
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c
index 1ce089d..4a475c6 100644
--- a/drivers/mmc/host/msm_sdcc.c
+++ b/drivers/mmc/host/msm_sdcc.c
@@ -966,6 +966,9 @@
 	void __iomem *base = host->base;
 	unsigned int pio_irqmask = 0;
 
+	BUG_ON(!data->sg);
+	BUG_ON(!data->sg_len);
+
 	host->curr.data = data;
 	host->curr.xfer_size = data->blksz * data->blocks;
 	host->curr.xfer_remain = host->curr.xfer_size;