fix(stm32mp1): set reset pulse duration to 31ms

According to ST Application note AN5256 [1], the minimum reset pulse
duration should be set to 31ms on boards powered with discrete
regulators.

[1] https://www.st.com/resource/en/application_note/dm00561921.pdf

Change-Id: Ib6ed029ee8a4b95f75a80948fdd2154b4ebe484f
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
1 file changed