ARM: ux500: remove unused regulator data

Most of the board-mop500-regulators.c file is never referenced and
can simply be removed.

Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>