block: pass block dev not num to read/write/erase()

This will allow the implementation to make use of data in the block_dev
structure beyond the base device number. This will be useful so that eMMC
block devices can encompass the HW partition ID rather than treating this
out-of-band. Equally, the existence of the priv field is crying out for
this patch to exist.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/common/cmd_read.c b/common/cmd_read.c
index f0fc9bf..8710288 100644
--- a/common/cmd_read.c
+++ b/common/cmd_read.c
@@ -66,7 +66,7 @@
 		return 1;
 	}
 
-	if (dev_desc->block_read(dev, offset + blk, cnt, addr) < 0) {
+	if (dev_desc->block_read(dev_desc, offset + blk, cnt, addr) < 0) {
 		printf("Error reading blocks\n");
 		return 1;
 	}