PPC 74xx_7xx: Fix build warnings for ELPPC board

Fix:

misc.c: In function 'misc_init_r':
misc.c:210:3: warning: dereferencing type-punned pointer will break
strict-aliasing rules [-Wstrict-aliasing]
misc.c:211:3: warning: dereferencing type-punned pointer will break
strict-aliasing rules [-Wstrict-aliasing]
misc.c:212:3: warning: dereferencing type-punned pointer will break
strict-aliasing rules [-Wstrict-aliasing]

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/board/eltec/elppc/misc.c b/board/eltec/elppc/misc.c
index 89f1b1d..4c3656e 100644
--- a/board/eltec/elppc/misc.c
+++ b/board/eltec/elppc/misc.c
@@ -207,9 +207,14 @@
 		buf[4] = eerev.etheraddr[5];
 		buf[5] = eerev.etheraddr[4];
 
-		*(unsigned short *) &buf[20] = 0x48B2;
-		*(unsigned short *) &buf[22] = 0x0004;
-		*(unsigned short *) &buf[24] = 0x1433;
+		buf[20] = 0x48;
+		buf[21] = 0xB2;
+
+		buf[22] = 0x00;
+		buf[23] = 0x04;
+
+		buf[24] = 0x14;
+		buf[25] = 0x33;
 
 		printf ("\nSRom:  Writing i82559 info ........ ");
 		if (eepro100_srom_store ((unsigned short *) buf) == -1)