msm: pil-gss: Remove GSS QGIC bus workaround from pil_gss_reset_trusted()

This workaround is now handled in secure context within the call
to pas_auth_and_reset(). Remove the unnecessary code. With recent
secure image builds, the accesses performed by the removed code
had no effect anyway, since the registers involved are protected
behind an XPU.

Change-Id: If2c34517e290f44a41980c9812fff1f21e8052b7
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>