plat/arm: Re-enable PIE when RESET_TO_BL31=1

Earlier PIE support was enabled for all arm platforms when
RESET_TO_BL31=1, but later on it was restricted only to FVP with patch
SHA d4580d17 because of n1sdp platform.

Now it has been verified that PIE does work for n1sdp platform also, so
enabling it again for all arm platforms.

Change-Id: I05ad4f1775ef72e7cb578ec9245cde3fbce971a5
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
3 files changed