kconfig: add blank Kconfig files

This would be useful to start moving various config options.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

drivers/Kconfig

@@ -0,0 +1,51 @@
+menu "Device Drivers"
+
+source "drivers/core/Kconfig"
+
+source "drivers/pci/Kconfig"
+
+source "drivers/pcmcia/Kconfig"
+
+source "drivers/mtd/Kconfig"
+
+source "drivers/block/Kconfig"
+
+source "drivers/misc/Kconfig"
+
+source "drivers/net/Kconfig"
+
+source "drivers/input/Kconfig"
+
+source "drivers/serial/Kconfig"
+
+source "drivers/tpm/Kconfig"
+
+source "drivers/i2c/Kconfig"
+
+source "drivers/spi/Kconfig"
+
+source "drivers/gpio/Kconfig"
+
+source "drivers/power/Kconfig"
+
+source "drivers/hwmon/Kconfig"
+
+source "drivers/watchdog/Kconfig"
+
+source "drivers/video/Kconfig"
+
+source "drivers/sound/Kconfig"
+
+source "drivers/usb/Kconfig"
+
+source "drivers/dfu/Kconfig"
+
+source "drivers/mmc/Kconfig"
+
+source "drivers/rtc/Kconfig"
+
+source "drivers/dma/Kconfig"
+
+source "drivers/crypto/Kconfig"
+
+endmenu