kvm: Move KVM_GET_XSAVE2 IOCTL definition at the end of kvm.h

This way we can more easily find the next free IOCTL number when
adding new IOCTLs.

Fixes: be50b206

 ("kvm: x86: Add support for getting/setting expanded xstate buffer")
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20220128154025.102666-1-frankja@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>