spyro: dts: improve the discharging thermal threthold to 55 degree

Too early to cut off the charging function, so increasing the
threthold to 55 degree, when the surface temp(quiet sensor) has
triggered, it will change to discharging status.

Change-Id: Ic7c9ebd2e6a755e67948ec582dc7597bad24d1c6
Signed-off-by: Jing Xue <jingxue@codeaurora.org>