Merge commit 'kvm-vmenter-load-store-regs' into HEAD

Merge commit 'kvm-vmenter-load-store-regs' into HEAD

Convert the repeated register save/restore sequences into macros,
trading some level of implementation trickiness for conciseness (more
than one register can be saved/restored with one invocation) and a
smaller chance of cut and paste errors between VMX and SVM files.

This becomes more useful with the upcoming support for APX, which
would need to add 32 lines to the VM entry/exit paths.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>