intel/jarrell: Fix missing include

To unconditionally get cmos_read().

Change-Id: I0af0e85c8a1f42113bd32b51c4e29e86b3c28112
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5228
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)

src/mainboard/intel/jarrell/watchdog.c

@@ -1,4 +1,5 @@
 #include <device/pnp_def.h>
+#include <pc80/mc146818rtc.h>
 
 #define NSC_WD_DEV PNP_DEV(0x2e, 0xa)
 #define NSC_WDBASE 0x600