gpio: lpc32xx: remove unused platform data file

ARM LPC32xx platform is device-tree only, there is no need to keep
a file with GPIO platform data structures, however some of macro
definitions should be moved to the driver code, which is the only user
of the removed header file.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>