wic: add 'part-name' argument for naming GPT partitions

The WIC's 'part' can now give a name for GPT partition in WKS file.
It's similar to '--label', but is naming partintions instead file systems.
It's required by some bootloaders to partitions have specified names.

(From OE-Core rev: 9b60e3466ed7cff0cea10815851eb1304002eb52)

Signed-off-by: Artur Mądrzak <artur@madrzak.eu>
Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/wic/plugins/imager/direct.py

@@ -366,6 +366,10 @@ class PartitionedImage():
         for num in range(len(self.partitions)):
             part = self.partitions[num]
 
+            if self.ptable_format == 'msdos' and part.part_name:
+                raise WicError("setting custom partition name is not " \
+                               "implemented for msdos partitions")
+
             if self.ptable_format == 'msdos' and part.part_type:
                 # The --part-type can also be implemented for MBR partitions,
                 # in which case it would map to the 1-byte "partition type"
@@ -519,6 +523,13 @@ class PartitionedImage():
             self._create_partition(self.path, part.type,
                                    parted_fs_type, part.start, part.size_sec)
 
+            if part.part_name:
+                logger.debug("partition %d: set name to %s",
+                             part.num, part.part_name)
+                exec_native_cmd("sgdisk --change-name=%d:%s %s" % \
+                                         (part.num, part.part_name,
+                                          self.path), self.native_sysroot)
+
             if part.part_type:
                 logger.debug("partition %d: set type UID to %s",
                              part.num, part.part_type)