bloblist: Add functions to obtain base address and size

Add a few convenience functions to obtain useful information about the
bloblist.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/bloblist.c b/test/bloblist.c
index c5788d5..720be7e 100644
--- a/test/bloblist.c
+++ b/test/bloblist.c
@@ -107,6 +107,8 @@
 	hdr = clear_bloblist();
 	ut_assertnull(bloblist_find(TEST_TAG, TEST_BLOBLIST_SIZE));
 	ut_assertok(bloblist_new(TEST_ADDR, TEST_BLOBLIST_SIZE, 0));
+	ut_asserteq(TEST_BLOBLIST_SIZE, bloblist_get_size());
+	ut_asserteq(TEST_ADDR, bloblist_get_base());
 	ut_asserteq(map_to_sysmem(hdr), TEST_ADDR);
 
 	/* Add a record and check that we can find it */