rcar_gen3: drivers: cpld: fix power-off on reset

rcar_gen3: drivers: cpld: fix power-off on reset

Method cpld_reset_cpu of bl31 is called from the Linux kernel and uses
GPIO6, GPIO2 pins as SPI bus lines to control the CPLD device. But in the
kernel GPIO6_8 pin are initialized to work in interrupt mode instead of
the input/output mode. This leads to the fact that the SPI bus becomes
non-functional. In this patch we switch the GPIO6_8 pin back to the
input-output mode.

Signed-off-by: Sergii Boryshchenko <sergii.boryshchenko@globallogic.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>