css/sgi: replace all uses of Clark with new product names

Replace all uses of 'SGI_CLARK' with 'RD_N1E1_EDGE' and
'SGI_CLARK_HELIOS' with 'RD_E1_EDGE' as per the updated product
names

Change-Id: Ib8136e421b1a46da1e5df58c6b1432d5c78d279b
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
3 files changed