mtd: spi-nor: drop \t after #define

Spacing is a little non-standard here. Fix up tabs vs. spaces.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Huang Shijie <b32955@freescale.com>
Reviewed-by: Marek Vasut <marex@denx.de>