Switch to TEST_CALLOC_NONNULL()

This removes some gubbins related to making sure the buffer is not NULL
that was previously cluttering the test case.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 8747660..41d7009 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -10381,12 +10381,8 @@
     uint8_t *dst_buffer = NULL;
     psa_status_t status;
 
-    /* Special case, when src_len or dst_len is 0, we want to test on a real
-     * buffer. Calling TEST_CALLOC with 0 will return NULL. */
-    size_t src_calloc_len = (src_len == 0 ? 1 : src_len);
-    size_t dst_calloc_len = (dst_len == 0 ? 1 : dst_len);
-    TEST_CALLOC(src_buffer, src_calloc_len);
-    TEST_CALLOC(dst_buffer, dst_calloc_len);
+    TEST_CALLOC_NONNULL(src_buffer, src_len);
+    TEST_CALLOC_NONNULL(dst_buffer, dst_len);
 
     fill_buffer_pattern(src_buffer, src_len);
 
@@ -10411,12 +10407,8 @@
     uint8_t *dst_buffer = NULL;
     psa_status_t status;
 
-    /* Special case, when src_len or dst_len is 0, we want to test on a real
-     * buffer. Calling TEST_CALLOC with 0 will return NULL. */
-    size_t src_calloc_len = (src_len == 0 ? 1 : src_len);
-    size_t dst_calloc_len = (dst_len == 0 ? 1 : dst_len);
-    TEST_CALLOC(src_buffer, src_calloc_len);
-    TEST_CALLOC(dst_buffer, dst_calloc_len);
+    TEST_CALLOC_NONNULL(src_buffer, src_len);
+    TEST_CALLOC_NONNULL(dst_buffer, dst_len);
 
     fill_buffer_pattern(src_buffer, src_len);