remove argument in snow's romstage main()

We don't pass any arguments into romstage on ARM.

Change-Id: I018f28a57fc486c9240345cf0f4043b79027d864
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/2162
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/mainboard/google/snow/romstage.c

@@ -26,7 +26,7 @@ static void mmu_setup(void)
 	dram_bank_mmu_setup(CONFIG_SYS_SDRAM_BASE, CONFIG_DRAM_SIZE_MB * 1024);
 }
 
-void main(unsigned long bist)
+void main(void)
 {
 	mmu_setup();
 }