arm64: defconfig: enable CONFIG_SPI_ARMADA_3700

The SPI is used on many boards (especially for the serial
flashes). Enable it by default.
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

arch/arm64/configs/defconfig

@@ -303,6 +303,7 @@ CONFIG_I2C_UNIPHIER_F=y
 CONFIG_I2C_RCAR=y
 CONFIG_I2C_CROS_EC_TUNNEL=y
 CONFIG_SPI=y
+CONFIG_SPI_ARMADA_3700=y
 CONFIG_SPI_MESON_SPICC=m
 CONFIG_SPI_MESON_SPIFC=m
 CONFIG_SPI_BCM2835=m