target-xtensa: fix tb invalidation for IBREAK and LOOP

Instruction breakpoint/zero overhead loop handling code is built into
TBs pointed to by IBREAKA/LEND SRs. When these or related SRs get
changed TBs at virtual addresses corresponding to their old and their
new values must be invalidated.

Virtual address range is passed to the tb_invalidate_phys_page_range,
which is incorrect in system emulation mode.

To fix it use guest TLB/MMU to translate virtual address to physical
address.

However the guest may not have virtual-to-physical mapping at the moment
of IBREAKA/LEND change, thus this fix is not 100% accurate.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
