Make legacy_or_psa.h public.

As a public header, it should no longer include common.h, just use
build_info.h which is what we actually need anyway.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index 9c04560..91fe869 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -8,7 +8,7 @@
 #include "mbedtls/rsa.h"
 
 #include "hash_info.h"
-#include "legacy_or_psa.h"
+#include "mbedtls/legacy_or_psa.h"
 
 #include <limits.h>
 #include <stdint.h>