pinctrl: rename U300 and SIRF pin controllers

For stringent order, rename the pinmux-* pin controllers to
pinctrl-* and also rename the Kconfig symbols and in-kernel
users.

Cc: Rongjun Ying <Rongjun.Ying@csr.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>