usb: dwc3: gadget: make dwc3 gadget build in uboot

Did a bunch of things to get dwc3/gadget.c compile in u-boot without
build errors and warnings
*) Changed the included header files to that used in u-boot.
*) Used dma_alloc_coherent and dma_free_coherent APIs of u-boot
*) removed sg support
*) remove jiffies and used a simple while loop
*) removed irq support and added a function to call these interrupt handler.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 6eac17f..6ff3915 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -326,6 +326,7 @@
 
 #define IRQ_NONE 0
 #define IRQ_HANDLED 1
+#define IRQ_WAKE_THREAD 2
 
 #define dev_set_drvdata(dev, data) do {} while (0)