vmw_balloon: include asm/io.h

vmw_balloon: include asm/io.h

BugLink: https://bugs.launchpad.net/bugs/1836287
commit a3b92ee6fc171d7c9d9b6b829b7fef169210440c upstream.

Fix a build error due to missing virt_to_phys()

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: f0a1bf29d821b ("vmw_balloon: fix inflation with batching")
Cc: stable@vger.kernel.org
Cc: Xavier Deguillard <xdeguillard@vmware.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>