newport_con: depend on LOGO_LINUX_CLUT224 instead of LOGO_SGI_CLUT224

newport_show_logo() is only activated if CONFIG_LOGO_SGI_CLUT224 is
set (otherwise it is a NOP). This configuration item will be removed
in an upcoming change so instead, make it depend on LOGO_LINUX_CLUT224.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>