tests: Add mbedtls_test_ prefix to unhexify_alloc()

Add mbedtls_test_ prefix to unhexify_alloc() test helper
functions.

Command to change *.function files:
find . -name "*.function" -exec awk -i inplace \
    '{sub(/unhexify_alloc\>/,"mbedtls_test_&")}1' {} \;

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/src/helpers.c b/tests/src/helpers.c
index 063ebcd..5f12501 100644
--- a/tests/src/helpers.c
+++ b/tests/src/helpers.c
@@ -113,7 +113,7 @@
     return( p );
 }
 
-unsigned char *unhexify_alloc( const char *ibuf, size_t *olen )
+unsigned char *mbedtls_test_unhexify_alloc( const char *ibuf, size_t *olen )
 {
     unsigned char *obuf;