headers: Fix build after <linux/sched.h> removal

Commit d43c36dc6b ("headers: remove
sched.h from interrupt.h") left some build errors in some configurations
due to drivers having depended on getting header files "accidentally".

Signed-off-by: Ingo Molnar <mingo@elte.hu>
[ Combined several one-liners from Ingo into one single patch  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/pci/hotplug/cpqphp.h

@@ -32,6 +32,7 @@
 #include <asm/io.h>		/* for read? and write? functions */
 #include <linux/delay.h>	/* for delays */
 #include <linux/mutex.h>
+#include <linux/sched.h>	/* for signal_pending() */
 
 #define MY_NAME	"cpqphp"