hwlat_detector: include linux/delay.h in hwlat_detector

This broke when compiling on i386 without X86_LOCAL_APIC because then
arch/x86/include/asm/smp.h doesn't include asm/apic.h which in turn includes
linux/delay.h.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Jon Masters <jcm@jonmasters.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

drivers/misc/hwlat_detector.c

@@ -49,6 +49,7 @@
 #include <linux/seq_file.h>
 #include <linux/uaccess.h>
 #include <linux/version.h>
+#include <linux/delay.h>
 
 #define BUF_SIZE_DEFAULT	262144UL		/* 8K*(sizeof(entry)) */
 #define BUF_FLAGS		(RB_FL_OVERWRITE)	/* no block on full */