b43: Fix possible unaligned u32 access

Fix possible unaligned u32 access in b43_generate_plcp_hdr().
Unaligned data is read/write with a u32 pointer instead of using the
packed structure. Some versions of gcc ignore the "packed" attribute, if the
structure element is accessed through a local pointer.
Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43/xmit.c

@@ -118,7 +118,6 @@ u8 b43_plcp_get_ratecode_ofdm(const u8 bitrate)
 void b43_generate_plcp_hdr(struct b43_plcp_hdr4 *plcp,
 			   const u16 octets, const u8 bitrate)
 {
-	__le32 *data = &(plcp->data);
 	__u8 *raw = plcp->raw;
 
 	if (b43_is_ofdm_rate(bitrate)) {
@@ -127,7 +126,7 @@ void b43_generate_plcp_hdr(struct b43_plcp_hdr4 *plcp,
 		d = b43_plcp_get_ratecode_ofdm(bitrate);
 		B43_WARN_ON(octets & 0xF000);
 		d |= (octets << 5);
-		*data = cpu_to_le32(d);
+		plcp->data = cpu_to_le32(d);
 	} else {
 		u32 plen;
 
@@ -141,7 +140,7 @@ void b43_generate_plcp_hdr(struct b43_plcp_hdr4 *plcp,
 				raw[1] = 0x04;
 		} else
 			raw[1] = 0x04;
-		*data |= cpu_to_le32(plen << 16);
+		plcp->data |= cpu_to_le32(plen << 16);
 		raw[0] = b43_plcp_get_ratecode_cck(bitrate);
 	}
 }