disk: part: implement generic function part_get_info_by_name()

So far partition search by name has been supported only on the EFI partition
table. This patch extends the search to all partition tables.

Rename part_get_info_efi_by_name() to part_get_info_by_name(), move it from
part_efi.c into part.c and make it a generic function which traverses all part
drivers and searches all partitions (in the order given by the linked list).

For this a new variable struct part_driver.max_entries is added, which limits
the number of partitions searched. For EFI this was GPT_ENTRY_NUMBERS.
Similarly the limit is defined for DOS, ISO, MAC and AMIGA partition tables.

Signed-off-by: Petr Kulhavy <brain@jikos.cz>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Steve Rae <steve.rae@raedomain.com>
diff --git a/disk/part.c b/disk/part.c
index 6a1c02d..8317e80 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -615,3 +615,29 @@
 	free(dup_str);
 	return ret;
 }
+
+int part_get_info_by_name(struct blk_desc *dev_desc, const char *name,
+	disk_partition_t *info)
+{
+	struct part_driver *first_drv =
+		ll_entry_start(struct part_driver, part_driver);
+	const int n_drvs = ll_entry_count(struct part_driver, part_driver);
+	struct part_driver *part_drv;
+
+	for (part_drv = first_drv; part_drv != first_drv + n_drvs; part_drv++) {
+		int ret;
+		int i;
+		for (i = 1; i < part_drv->max_entries; i++) {
+			ret = part_drv->get_info(dev_desc, i, info);
+			if (ret != 0) {
+				/* no more entries in table */
+				break;
+			}
+			if (strcmp(name, (const char *)info->name) == 0) {
+				/* matched */
+				return 0;
+			}
+		}
+	}
+	return -1;
+}