Rename Cortex-Helios filenames to Neoverse E1

Change-Id: I33bdb9df0462b056adbd00922b2e73eb720560b3
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>
diff --git a/include/lib/cpus/aarch64/cortex_helios.h b/include/lib/cpus/aarch64/neoverse_e1.h
similarity index 100%
rename from include/lib/cpus/aarch64/cortex_helios.h
rename to include/lib/cpus/aarch64/neoverse_e1.h
diff --git a/lib/cpus/aarch64/cortex_helios.S b/lib/cpus/aarch64/neoverse_e1.S
similarity index 100%
rename from lib/cpus/aarch64/cortex_helios.S
rename to lib/cpus/aarch64/neoverse_e1.S