usb: f_uac2: Add support for UAC2 function

Add support for the UAC2 function with the configfs
framework.
Also fix the audio quality issues by increasing the
number of USB_XFERS.

Change-Id: Ie94aee43dd52b0b711778420e485af72730dd28b
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>
diff --git a/drivers/usb/gadget/function/u_uac2.h b/drivers/usb/gadget/function/u_uac2.h
index 78dd372..f7d2d44 100644
--- a/drivers/usb/gadget/function/u_uac2.h
+++ b/drivers/usb/gadget/function/u_uac2.h
@@ -22,7 +22,7 @@
 #define UAC2_DEF_PSRATE 48000
 #define UAC2_DEF_PSSIZE 2
 #define UAC2_DEF_CCHMASK 0x3
-#define UAC2_DEF_CSRATE 64000
+#define UAC2_DEF_CSRATE 44100
 #define UAC2_DEF_CSSIZE 2
 
 struct f_uac2_opts {