mpc83xx: Make it boot again

After the removal of COLD/WARM start flags my mpc8321
board didn't boot anymore.
Trial and error suggests that map/remap_flash_by_xxx needs
to wait after updating LBLAWAR1 to make sure the the change has
reached the HW before continuing with the code that depends on it.
Final fix suggested by Scott Wood.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>

arch/powerpc/cpu/mpc83xx/start.S

@@ -1158,6 +1158,10 @@ map_flash_by_law1:
 	bne 1b
 
 	stw r4, LBLAWAR1(r3) /* LBLAWAR1 <= 8MB Flash Size */
+	/* Wait for HW to catch up */
+	lwz r4, LBLAWAR1(r3)
+	twi 0,r4,0
+	isync
 	blr
 
 	/* Though all the LBIU Local Access Windows and LBC Banks will be
@@ -1196,5 +1200,9 @@ remap_flash_by_law0:
 	xor r4, r4, r4
 	stw r4, LBLAWBAR1(r3)
 	stw r4, LBLAWAR1(r3) /* Off LBIU LAW1 */
+	/* Wait for HW to catch up */
+	lwz r4, LBLAWAR1(r3)
+	twi 0,r4,0
+	isync
 	blr
 #endif /* CONFIG_SYS_FLASHBOOT */