Convert CONFIG_DW_ALTDESCRIPTOR to Kconfig

This converts the following to Kconfig:
   CONFIG_DW_ALTDESCRIPTOR

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/galileo_defconfig b/configs/galileo_defconfig
index 104532b..5ae13d5 100644
--- a/configs/galileo_defconfig
+++ b/configs/galileo_defconfig
@@ -49,6 +49,7 @@
 CONFIG_REGMAP=y
 CONFIG_SYSCON=y
 CONFIG_CPU=y
+CONFIG_DW_ALTDESCRIPTOR=y
 CONFIG_SPI=y
 CONFIG_USB_STORAGE=y
 CONFIG_USB_KEYBOARD=y