SVN r322588 breaks non-SMP kernel build

[Michael Butler]

Building on an i386 without SMP after SVN r322588 yields this breakage:

Building /usr/obj/usr/src/sys/SARAH/intr_machdep.o
--- intr_machdep.o ---
/usr/src/sys/x86/x86/intr_machdep.c:78:23: warning: variable 
'interrupt_sorted' is not needed and will not be emitted 
[-Wunneeded-internal-declaration]
static struct intsrc *interrupt_sorted[NUM_IO_INTS];
                       ^
/usr/src/sys/x86/x86/intr_machdep.c:83:28: error: unused variable 
'intrbalance_task' [-Werror,-Wunused-variable]
static struct timeout_task intrbalance_task;
                            ^
1 warning and 1 error generated.
*** [intr_machdep.o] Error code 1

	imb