Import data cache clean and invalidation helpers

As a follow-up to 8077591cc5154a replace earlier cache maintenance
functions by ones imported from TF-A project (data cache clean and
invalidation), from the following files:
https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/tree/
lib/aarch64/cache_helpers.S?h=v2.4
https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/tree/
include/arch/aarch64/asm_macros.S?h=v2.4

Change-Id: Iab55bd2cfa006507f811c6f396db3a8fe3160580
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/src/cpu.c b/src/cpu.c
index 42c2428..bc26801 100644
--- a/src/cpu.c
+++ b/src/cpu.c
@@ -119,9 +119,9 @@
 	 * hitting the entry point can read the cpus array consistently
 	 * with MMU off (hence data cache off).
 	 */
-	arch_cache_clean_range(va_from_ptr(cpus), sizeof(cpus));
+	arch_cache_data_clean_range(va_from_ptr(cpus), sizeof(cpus));
 
-	arch_cache_clean_range(va_from_ptr(&cpu_count), sizeof(cpu_count));
+	arch_cache_data_clean_range(va_from_ptr(&cpu_count), sizeof(cpu_count));
 }
 
 size_t cpu_index(struct cpu *c)