KVM: PPC: e500mc: Fix tlbilx emulation for 64-bit guests

tlbilxva emulation was using an u32 variable for guest effective address.
Replace it with gva_t type to handle 64-bit guests.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>