[MTD] Fix mtdoops.c compilation

drivers/mtd/mtdoops.c: In function ‘mtdoops_console_sync’:
drivers/mtd/mtdoops.c:329: error: implicit declaration of function ‘in_interrupt’

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/mtdoops.c

@@ -30,6 +30,7 @@
 #include <linux/wait.h>
 #include <linux/delay.h>
 #include <linux/spinlock.h>
+#include <linux/interrupt.h>
 #include <linux/mtd/mtd.h>
 
 #define OOPS_PAGE_SIZE 4096