hw/xtensa: allow reads/writes in the system io region

This makes drivers for unimportant unimplemented hardware block happy.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: implement do_unassigned_access callback

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
WIP: target-xtensa: add GPIO32 coprocessor

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
WIP: target-xtensa: add definition for XTHAL_INTTYPE_PROFILING

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: add test_kc705_ca core

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: rename and publish tb_invalidate_virtual_addr

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: extract floating point helpers

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: extract windowed registers helpers

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: extract MMU helpers

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: extract debug helpers

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
target-xtensa: extract exceptions helpers

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