boot: android: Fix ramdisk loading for v2 header

boot: android: Fix ramdisk loading for v2 header

Before
commit da3447d09fa0 ("android: Fix ramdisk loading for bootimage v3+"),
the ramdisk was loaded from img_data.ramdisk_ptr, ignoring offset
provided via mkbootimg.

commit da3447d09fa0 ("android: Fix ramdisk loading for bootimage v3+")
rightfully fixes this by switching to use img_data.ramdisk_addr instead.

However, it does not copy the ramdisk content to img_data.ramdisk_addr
in case we use boot image v2.

Because of this, we can no longer boot Android on Khadas vim3 board:

[    3.940361] RAMDISK: Couldn't find valid RAM disk image starting at 0.

Add the missing memcpy() to fix the issue.

Fixes: da3447d09fa0 ("android: Fix ramdisk loading for bootimage v3+")
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>