[ARM] Fix VTEMU creation in arch_board_final_init()

With recent updates in drivers/video/fbmem.c results in fb_info
instances with name fb0, fb1, ..., fbX. There is no relation between
device tree node name and fb_info instance name hence we create VTEMU
instance with same name as fb_info instance (i.e. fb0, fb1, ..., fbX).

Signed-off-by: Anup Patel <anup@brainfault.org>