rockchip: mkimage: Print image information for all embedded images

The v2 image format can embed up to 4 data files compared to the two
init and boot data files using the older image format.

Add support for displaying more of the image header information that
exists in the v2 image format, e.g. image load address and flag.

Example for v2 image format:

  > tools/mkimage -l rk3576_idblock_v1.09.107.img
  Rockchip Boot Image (v2)
  Image 1: 4096 @ 0x1000
  - Load address: 0x3ffc0000
  Image 2: 77824 @ 0x2000
  - Load address: 0x3ff81000
  Image 3: 262144 @ 0x15000

Example for older image format:

  > tools/mkimage -l u-boot-rockchip.bin
  Rockchip RK32 (SD/MMC) Boot Image
  Init Data: 20480 @ 0x800
  Boot Data: 112640 @ 0x5800

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>