x86/vmi: fix interrupt enable/disable/save/restore calling convention.

Zach says:
> Enable/Disable have no clobbers at all.
> Save clobbers only return value, %eax
> Restore also clobbers nothing.

This is precisely compatible with the calling convention, so we can
just call them directly without wrapping.

(Compile tested only.)

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/vmi_32.c

@@ -670,10 +670,11 @@ static inline int __init activate_vmi(void)
 	para_fill(pv_mmu_ops.write_cr2, SetCR2);
 	para_fill(pv_mmu_ops.write_cr3, SetCR3);
 	para_fill(pv_cpu_ops.write_cr4, SetCR4);
-	para_fill(pv_irq_ops.save_fl, GetInterruptMask);
-	para_fill(pv_irq_ops.restore_fl, SetInterruptMask);
-	para_fill(pv_irq_ops.irq_disable, DisableInterrupts);
-	para_fill(pv_irq_ops.irq_enable, EnableInterrupts);
+
+	para_fill(pv_irq_ops.save_fl.func, GetInterruptMask);
+	para_fill(pv_irq_ops.restore_fl.func, SetInterruptMask);
+	para_fill(pv_irq_ops.irq_disable.func, DisableInterrupts);
+	para_fill(pv_irq_ops.irq_enable.func, EnableInterrupts);
 
 	para_fill(pv_cpu_ops.wbinvd, WBINVD);
 	para_fill(pv_cpu_ops.read_tsc, RDTSC);