remove __attribute__ ((packed)) in at91 headers

* remove __attribute__ ((packed)) to prevent byte access
  to soc registers in some gcc version

Signed-off-by: Jens Scharsig <js_at_ng@scharsoft.de>
diff --git a/arch/arm/include/asm/arch-at91/at91_st.h b/arch/arm/include/asm/arch-at91/at91_st.h
index 53f9320..98b0a76 100644
--- a/arch/arm/include/asm/arch-at91/at91_st.h
+++ b/arch/arm/include/asm/arch-at91/at91_st.h
@@ -35,7 +35,7 @@
 	u32	imr;
 	u32	rtar;
 	u32	crtr;
-} __attribute__ ((packed)) at91_st_t ;
+} at91_st_t ;
 
 #define AT91_ST_CR_WDRST	1