xtensa: virt: move PCI root complex to KIO range

Move PCI configuration space, MMIO and memory to the KIO range to free
vmalloc area and use static TLB to access them. Move MMIO to the
beginning of KIO and define PCI_IOBASE as XCHAL_KIO_BYPASS_VADDR to
match it. Reduce number of supported PCI buses to 0x3f so that ECAM
window fits into first 64MB of the KIO. Reduce size of the PCI memory
window to 128MB so that it fits into KIO.

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