mtd: rawnand: ingenic: Add dependency on MIPS || COMPILE_TEST

This driver has no arch-specific instructions but is only ever useful
on MIPS; so disable this driver if we're not compiling for MIPS, unless
the driver is compile-tested.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200302184509.10666-1-paul@crapouillou.net

drivers/mtd/nand/raw/ingenic/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
 config MTD_NAND_JZ4780
 	tristate "JZ4780 NAND controller"
+	depends on MIPS || COMPILE_TEST
 	depends on JZ4780_NEMC
 	help
 	  Enables support for NAND Flash connected to the NEMC on JZ4780 SoC