Disable low speed SPI controller

On Optimus and Sideswipe, the low speed SPI controller is not connected
except on some very early boards. Also, its FIFO is only 8 words deep.
(The high speed SPI controller has a 32-word FIFO).

Change-Id: I0d9f8d605dd8398349f0ed10b42ee7d60e0c6724
diff --git a/arch/arm/configs/gfrg200_defconfig b/arch/arm/configs/gfrg200_defconfig
index cdb1649..fbcd630 100644
--- a/arch/arm/configs/gfrg200_defconfig
+++ b/arch/arm/configs/gfrg200_defconfig
@@ -241,6 +241,7 @@
 CONFIG_I2C_COMCERTO=y
 CONFIG_SPI=y
 CONFIG_SPI_DEBUG=y
+# CONFIG_SPI_MSPD_LOW_SPEED is not set
 CONFIG_HWMON_DEBUG_CHIP=y
 CONFIG_SENSORS_LM63=y
 CONFIG_WATCHDOG=y