x86, nmi, drivers: Fix nmi splitup build bug

nmi.c needs an #include <linux/mca.h>:

 arch/x86/kernel/nmi.c: In function ‘unknown_nmi_error’:
 arch/x86/kernel/nmi.c:286:6: error: ‘MCA_bus’ undeclared (first use in this function)
 arch/x86/kernel/nmi.c:286:6: note: each undeclared identifier is reported only once for each function it appears in

Another one is the hpwdt driver:

 drivers/watchdog/hpwdt.c:507:9: error: ‘NMI_DONE’ undeclared (first use in this function)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/nmi.c

@@ -18,6 +18,8 @@
 #include <linux/hardirq.h>
 #include <linux/slab.h>
 
+#include <linux/mca.h>
+
 #if defined(CONFIG_EDAC)
 #include <linux/edac.h>
 #endif

drivers/watchdog/hpwdt.c

@@ -35,6 +35,7 @@
 #include <linux/notifier.h>
 #include <asm/cacheflush.h>
 #endif /* CONFIG_HPWDT_NMI_DECODING */
+#include <asm/nmi.h>
 
 #define HPWDT_VERSION			"1.3.0"
 #define SECS_TO_TICKS(secs)		((secs) * 1000 / 128)