USB: Use (get|put)_unaligned for accessing wMaxPacketSize

In 9792987721c7980453fe6447c3fa6593b44f8458 Stefan describes a usecase
where the previous behavior of leaving wMaxPacketSize be unaligned
caused fatal problems.  The initial fix for this problem was incomplete
however as it showed another cases of non-aligned access that previously
worked implicitly.  This switches to making sure that all access of
wMaxPacketSize are done via (get|put)_unaligned.

In order to maintain a level of readability to the code in some cases
we now use a variable for the value of wMaxPacketSize and in others, a
macro.

Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Remy Bohmer <linux@bohmer.net>

OpenRISC:
Tested-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>

Beagleboard xM, Pandaboard run-tested, s5p_goni build-tested.
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/include/usbdescriptors.h b/include/usbdescriptors.h
index 392fcf5..2dec3b9 100644
--- a/include/usbdescriptors.h
+++ b/include/usbdescriptors.h
@@ -199,7 +199,7 @@
 	u8 bmAttributes;
 	u16 wMaxPacketSize;
 	u8 bInterval;
-} __attribute__ ((packed)) __attribute__ ((aligned(2)));
+} __attribute__ ((packed));
 
 struct usb_interface_descriptor {
 	u8 bLength;