xtensa/uaccess: fix sparse errors

virtio wants to read bitwise types from userspace using get_user.  At the
moment this triggers sparse errors, since the value is passed through an
integer.

Fix that up using __force.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/include/asm/uaccess.h

@@ -320,7 +320,7 @@ __asm__ __volatile__(					\
 ({								\
 	long __gu_err, __gu_val;				\
 	__get_user_size(__gu_val,(ptr),(size),__gu_err);	\
-	(x) = (__typeof__(*(ptr)))__gu_val;			\
+	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
 	__gu_err;						\
 })
 
@@ -330,7 +330,7 @@ __asm__ __volatile__(					\
 	const __typeof__(*(ptr)) *__gu_addr = (ptr);			\
 	if (access_ok(VERIFY_READ,__gu_addr,size))			\
 		__get_user_size(__gu_val,__gu_addr,(size),__gu_err);	\
-	(x) = (__typeof__(*(ptr)))__gu_val;				\
+	(x) = (__force __typeof__(*(ptr)))__gu_val;				\
 	__gu_err;							\
 })