test_suite_pkwrite: replace memcpy with memmove

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/tests/suites/test_suite_pkwrite.function b/tests/suites/test_suite_pkwrite.function
index 7cc845a..c0c5ad0 100644
--- a/tests/suites/test_suite_pkwrite.function
+++ b/tests/suites/test_suite_pkwrite.function
@@ -18,7 +18,7 @@
         if (in_str[i] == '\r') {
             if (i < (*len - 1)) {
                 chars_left = *len - i - 1;
-                memcpy(&in_str[i], &in_str[i+1], chars_left);
+                memmove(&in_str[i], &in_str[i+1], chars_left);
             } else {
                 in_str[i] = '\0';
             }