x86: iommu_sac_force can become static

The iommu_sac_force variable is needlessly defined global,
and this patch makes it static. Additionally, this variable
needs not be explicitly initialized.
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/pci-dma.c

@@ -14,7 +14,7 @@ EXPORT_SYMBOL(forbid_dac);
 const struct dma_mapping_ops *dma_ops;
 EXPORT_SYMBOL(dma_ops);
 
-int iommu_sac_force __read_mostly = 0;
+static int iommu_sac_force __read_mostly;
 
 #ifdef CONFIG_IOMMU_DEBUG
 int panic_on_overflow __read_mostly = 1;