gpio: tc35894: fix up tc35894 interrupt configuration

The offset of regmap is incorrect, j * 8 is move to the
wrong register.

for example:

asume i = 0, j = 1. we want to set KPY5 as interrupt
falling edge mode, regmap[0][1] should be TC3589x_GPIOIBE1 0xcd
but, regmap[i] + j * 8 = TC3589x_GPIOIBE0 + 8 ,point to 0xd4,
this is TC3589x_GPIOIE2 not TC3589x_GPIOIBE1.

Fixes: d88b25be

 ("gpio: Add TC35892 GPIO driver")
Cc: Cc: stable@vger.kernel.org
Signed-off-by: dillon min <dillon.minfei@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>