commonlib/bsd: Add struct name "mem_chip_channel" for external access

struct mem_chip_info {
  ...
  struct { --> If no struct name, can't access the channel structure
    ...
  } channel[0];
};

BUG=b:182963902,b:177917361
TEST=Build pass on Kingler

Signed-off-by: Xi Chen <xixi.chen@mediatek.corp-partner.google.com>
Change-Id: I8dcd3b52f33f80afb7885ffdcad826d86b54b543
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62850
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>

src/commonlib/bsd/include/commonlib/bsd/mem_chip_info.h

@@ -15,7 +15,7 @@ struct mem_chip_info {
 	uint8_t type;  /* enum mem_chip_type */
 	uint8_t num_channels;
 	uint8_t reserved[6];
-	struct {
+	struct mem_chip_channel {
 		uint64_t density;
 		uint8_t io_width;
 		uint8_t manufacturer_id;