mtd: st_spi_fsm: fixup Kconfig dependency

I hear that this driver should depend on ARCH_STI, and that "SH" is not
actually a real symbol. At the same time, let's allow compile-testing on
other ARCH'es.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Marek Vasut <marex@denx.de>

drivers/mtd/devices/Kconfig

@@ -212,7 +212,7 @@ config MTD_DOCG3
 
 config MTD_ST_SPI_FSM
 	tristate "ST Microelectronics SPI FSM Serial Flash Controller"
-	depends on ARM || SH
+	depends on ARCH_STI || COMPILE_TEST
 	help
 	  This provides an MTD device driver for the ST Microelectronics
 	  SPI Fast Sequence Mode (FSM) Serial Flash Controller and support