fix(cpus): put back the global declaration for erratum #3701747

Patch 89dba82df accidentally removed it. Put it back.

Change-Id: Ic7a5a13ae89b0b86ccbea56fecfe12bef57a90b9
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
diff --git a/lib/cpus/aarch64/cortex_x925.S b/lib/cpus/aarch64/cortex_x925.S
index 003dc97..fd95073 100644
--- a/lib/cpus/aarch64/cortex_x925.S
+++ b/lib/cpus/aarch64/cortex_x925.S
@@ -35,6 +35,7 @@
 
 add_erratum_entry cortex_x925, ERRATUM(3701747), ERRATA_X925_3701747
 
+.global check_erratum_cortex_x925_3701747
 check_erratum_ls cortex_x925, ERRATUM(3701747), CPU_REV(0, 1)
 
 workaround_reset_start cortex_x925, ERRATUM(2963999), ERRATA_X925_2963999