Fix build error when enable VGA console.

drivers/video/console/vgacon.c:586: undefined reference to `screen_info'

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>

Fix the following compiler splat by adding __maybe_unused annotation to
the variable. Using this particular annotation has the least ugly impact
on the code compared to using ifdeffery.

arch/nios2/kernel/setup.c: In function 'nios2_boot_init':
arch/nios2/kernel/setup.c:107:7: warning: unused variable 'cmdline_passed' [-Wunused-variable]
  char cmdline_passed[COMMAND_LINE_SIZE] = { 0, };
       ^

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Ley Foon Tan <lftan@altera.com>

Signed-off-by: Ley Foon Tan <lftan@altera.com>

This patch adds the kernel booting and the initial setup code.

Signed-off-by: Ley Foon Tan <lftan@altera.com>