xtensa: adjust boot parameters address when INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX is selected

commit c5a771d0678f9613e9f89cf1a5bdcfa5b08b225b upstream.

The virtual address of boot parameters chain is passed to the kernel via
a2 register. Adjust it in case it is remapped during MMUv3 -> MMUv2
mapping change, i.e. when it is in the first 128M.

Also fix interpretation of initrd and FDT addresses passed in the boot
parameters: these are physical addresses.

Reported-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>