On some new platforms the tiles have been placed too far apart to be
covered in a single ioremap. Turn "regs" into an array of base addresses
and make the pingroup carry the information about which tile the pin
resides in.

For existing platforms we map the first entry regs and the existing
pingroups will all use tile 0, meaning that there's no functional
change.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>