xen/arm: traps: Export a bunch of helpers to handle emulation

xen/arm: traps: Export a bunch of helpers to handle emulation

A follow-up patch will move some parts of traps.c in separate files.
The will require to use helpers that are currently statically defined.
Export the following helpers:
    - inject_undef64_exception
    - inject_undef_exception
    - check_conditional_instr
    - advance_pc
    - handle_raz_wi
    - handle_wo_wi
    - handle_ro_raz

Note that asm-arm/arm32/traps.h is empty but it is to keep parity with
the arm64 counterpart.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>