x86/UV: Fix conditional in gru_exit() (bsc#909095).

suse-commit: 9227b9127e1d80ee60f4fd133ca8fe6d55446adb
x86/uv: Update the UV3 TLB shootdown logic (bsc#909092).

suse-commit: 27d15fb49cd3ab49e093e1142bc31976b2afd56a