ARC: unbork module link errors with !CONFIG_ARC_HAS_LLSC

|  SYSMAP  System.map
|  Building modules, stage 2.
|  MODPOST 18 modules
|ERROR: "smp_atomic_ops_lock" [drivers/gpu/drm/drm_kms_helper.ko] undefined!
|ERROR: "smp_bitops_lock" [drivers/gpu/drm/drm_kms_helper.ko] undefined!
|ERROR: "smp_atomic_ops_lock" [drivers/gpu/drm/drm.ko] undefined!
| ERROR: "smp_bitops_lock" [drivers/gpu/drm/drm.ko] undefined!
|../scripts/Makefile.modpost:91: recipe for target '__modpost' failed

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/kernel/smp.c

@@ -23,6 +23,8 @@
 #include <linux/cpumask.h>
 #include <linux/reboot.h>
 #include <linux/irqdomain.h>
+#include <linux/export.h>
+
 #include <asm/processor.h>
 #include <asm/setup.h>
 #include <asm/mach_desc.h>
@@ -30,6 +32,9 @@
 #ifndef CONFIG_ARC_HAS_LLSC
 arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+EXPORT_SYMBOL_GPL(smp_atomic_ops_lock);
+EXPORT_SYMBOL_GPL(smp_bitops_lock);
 #endif
 
 struct plat_smp_ops  __weak plat_smp_ops;