avr32: Fix wrong I/O access size in __raw_readsb

__raw_readsb() should always use byte accesses, never halfword accesses,
to I/O memory.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/arch/avr32/lib/io-readsb.S b/arch/avr32/lib/io-readsb.S
index 2be5da7..cb2d869 100644
--- a/arch/avr32/lib/io-readsb.S
+++ b/arch/avr32/lib/io-readsb.S
@@ -41,7 +41,7 @@
 2:	sub	r10, -4
 	reteq	r12
 
-3:	ld.uh	r8, r12[0]
+3:	ld.ub	r8, r12[0]
 	sub	r10, 1
 	st.b	r11++, r8
 	brne	3b