Revert "Adding GSI keys"

This reverts commit f8c6fee371f34b2dcb47435c0ad4f59132380e8f.
Taimen has no first-stage ramdisk and there is no need to install
GSI keys there.

Bug: 140873290
Test: tree hugger
Change-Id: I0b4bfdcc32718824ff5acb2b0263d7fe8aa2df63
1 file changed