target-mips: get_physical_address: Add KVM awareness

target-mips: get_physical_address: Add KVM awareness

MIPS KVM trap & emulate mode (which is currently the only supported
mode) has to add an extra kseg0/kseg1 at 0x40000000 and an extra
kseg2/kseg3 at 0x60000000. Take this into account in
get_physical_address() so that debug memory access works.

This is done by translating the address to a standard kseg0 or kseg2
address before doing the normal address translation. The real virtual
address is still used for TLB lookups.

Signed-off-by: James Hogan <[email protected]>
Cc: Aurelien Jarno <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>