mmc: emmc and hw partitions partition table id bugfix.

On bootup the emmc's hw partition is always set to 0 and the partition
table is read from it. When switching to another hw partition the
partition table's id is not updated but instead the old one from
hw partition 0 is used. If there is no partition table on hw partition 0
then the code will terminate and return error even if the desired hw
partition contains a perfectly fine partition table. This fix updates
the partition table struct to correspond to the specified hw partition
before testing if the partition table is valid or not.

Signed-off-by: Erik Tideman <erik.tideman@faltcom.se>
Reviewed-by: Tom Rini <trini@konsulko.com>
[trini: Squash the patch that corrected whitespace in the original into
this one, wrap with HAVE_BLOCK_DEVICE test]
Signed-off-by: Tom Rini <trini@konsulko.com>

disk/part.c

@@ -493,6 +493,16 @@ int get_device(const char *ifname, const char *dev_hwpart_str,
 		goto cleanup;
 	}
 
+#ifdef HAVE_BLOCK_DEVICE
+	/*
+	 * Updates the partition table for the specified hw partition.
+	 * Does not need to be done for hwpart 0 since it is default and
+	 * already loaded.
+	 */
+	if(hwpart != 0)
+		init_part(*dev_desc);
+#endif
+
 cleanup:
 	free(dup_str);
 	return dev;