ARM: omap: allow building omap44xx without SMP

The new omap4 cpuidle implementation currently requires
ARCH_NEEDS_CPU_IDLE_COUPLED, which only works on SMP.

This patch makes it possible to build a non-SMP kernel
for that platform. This is not normally desired for
end-users but can be useful for testing.

Without this patch, building rand-0y2jSKT results in:

drivers/cpuidle/coupled.c: In function 'cpuidle_coupled_poke':
drivers/cpuidle/coupled.c:317:3: error: implicit declaration of function '__smp_call_function_single' [-Werror=implicit-function-declaration]

It's not clear if this patch is the best solution for
the problem at hand. I have made sure that we can now
build the kernel in all configurations, but that does
not mean it will actually work on an OMAP44xx.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/cpuidle44xx.c b/arch/arm/mach-omap2/cpuidle44xx.c
index ee05e19..288bee6 100644
--- a/arch/arm/mach-omap2/cpuidle44xx.c
+++ b/arch/arm/mach-omap2/cpuidle44xx.c
@@ -238,8 +238,9 @@
 	for_each_cpu(cpu_id, cpu_online_mask) {
 		dev = &per_cpu(omap4_idle_dev, cpu_id);
 		dev->cpu = cpu_id;
+#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 		dev->coupled_cpus = *cpu_online_mask;
-
+#endif
 		cpuidle_register_driver(&omap4_idle_driver);
 
 		if (cpuidle_register_device(dev)) {