boards: mimxrt1010_evk: Set User Button pull-up option bit

Set GPIO pull-up option bit (GPIO_PULL_UP) in DTS for User Button
on NXP MIMXRT1010-EVK. This fixes an issue with the detection of
the low active input signal from the button as GPIO key. Zephyr's
basic sample "button" will now work with this correctly.

Signed-off-by: Stephan Linz <linz@li-pro.net>