disk: dos: rename write_mbr_partition to write_mbr_sector

write_mbr_partition() function name is a bit misleading, so rename it to
write_mbr_sector(). This is a preparation for adding code for writing a
complete MBR partition layout.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

disk/part_dos.c

@@ -329,7 +329,7 @@ int is_valid_dos_buf(void *buf)
 	return test_block_type(buf) == DOS_MBR ? 0 : -1;
 }
 
-int write_mbr_partition(struct blk_desc *dev_desc, void *buf)
+int write_mbr_sector(struct blk_desc *dev_desc, void *buf)
 {
 	if (is_valid_dos_buf(buf))
 		return -1;