kernel/up.c: omit it if SMP=y, USE_GENERIC_SMP_HELPERS=n

Fix the sparc build - we were including `up.o' on SMP builds, when
CONFIG_USE_GENERIC_SMP_HELPERS=n.

Tested-by: Robert Reif <[e-mail]>
Fixed-by: Robert Reif <[e-mail]>
Cc: David Miller <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/Makefile

···
 obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
 obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
-ifeq ($(CONFIG_USE_GENERIC_SMP_HELPERS),y)
-obj-y += smp.o
-else
+obj-$(CONFIG_USE_GENERIC_SMP_HELPERS) += smp.o
+ifneq ($(CONFIG_SMP),y)
 obj-y += up.o
 endif
 obj-$(CONFIG_SMP) += spinlock.o