sh-pfc: sh73a0: Introduce the use of devm_regulator_register

sh-pfc: sh73a0: Introduce the use of devm_regulator_register

This patch moves data allocated using regulator_register to
devm_regulator_register and does away the calls to regulator_unregister.
The sh73a0_pinmux_soc_exit function is no longer needed and is removed.

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
(cherry picked from commit 01a7d13a8cfa6424a9568f3c7e925ace57cd3fc8)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>