x86/vpmu: Remove unnecessary call to do_interrupt()

x86/vpmu: Remove unnecessary call to do_interrupt()

This call was left during PVHv1 removal (commit 33e5c32559e1 ("x86:
remove PVHv1 code")):

-        if ( is_pvh_vcpu(sampling) &&
-             !(vpmu_mode & XENPMU_MODE_ALL) &&
+        if ( !(vpmu_mode & XENPMU_MODE_ALL) &&
              !vpmu->arch_vpmu_ops->do_interrupt(regs) )
             return;

As result of this extra call VPMU no longer works for PV guests on Intel
because we effectively lose value of MSR_CORE_PERF_GLOBAL_STATUS.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Julien Grall <julien.grall@linaro.org>