KVM: selftests: fix vmx_preemption_timer_test build with GCC10

GCC10 fails to build vmx_preemption_timer_test:

gcc -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99
-fno-stack-protector -fno-PIE -I../../../../tools/include
 -I../../../../tools/arch/x86/include -I../../../../usr/include/
 -Iinclude -Ix86_64 -Iinclude/x86_64 -I..  -pthread  -no-pie
 x86_64/evmcs_test.c ./linux/tools/testing/selftests/kselftest_harness.h
 ./linux/tools/testing/selftests/kselftest.h
 ./linux/tools/testing/selftests/kvm/libkvm.a
 -o ./linux/tools/testing/selftests/kvm/x86_64/evmcs_test
/usr/bin/ld: ./linux/tools/testing/selftests/kvm/libkvm.a(vmx.o):
 ./linux/tools/testing/selftests/kvm/include/x86_64/vmx.h:603:
 multiple definition of `ctrl_exit_rev'; /tmp/ccMQpvNt.o:
 ./linux/tools/testing/selftests/kvm/include/x86_64/vmx.h:603:
 first defined here
/usr/bin/ld: ./linux/tools/testing/selftests/kvm/libkvm.a(vmx.o):
 ./linux/tools/testing/selftests/kvm/include/x86_64/vmx.h:602:
 multiple definition of `ctrl_pin_rev'; /tmp/ccMQpvNt.o:
 ./linux/tools/testing/selftests/kvm/include/x86_64/vmx.h:602:
 first defined here
 ...

ctrl_exit_rev/ctrl_pin_rev/basic variables are only used in
vmx_preemption_timer_test.c, just move them there.

Fixes: 8d7fbf01 ("KVM: selftests: VMX preemption timer migration test")
Reported-by: Marcelo Bandeira Condotta <mcondotta@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200608112346.593513-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>