fix(imx8mp): change the BL31 physical load address

Change BL31 load address to 0x970000. This was done by Change-Id
I96d572fc. But then changed back to 0x960000 by Change-Id I8308c629.
However, 0x970000 is the correct value thus we change it back again.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Change-Id: Ia0db4877123b89072f723d18e2bcce25ef38f47d
1 file changed