plat: imx7: refactor code for reuse

For the iMX7 SOCs, part of the code for platform
setup implementation can be reused and made
common for all these SoCs. This patch extracts
the common part for reuse.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Change-Id: I42fd4167e6903416df96a0159a046abf3896e878
diff --git a/plat/imx/imx7/common/imx7_trusted_boot.c b/plat/imx/imx7/common/imx7_trusted_boot.c
new file mode 100644
index 0000000..cd27128
--- /dev/null
+++ b/plat/imx/imx7/common/imx7_trusted_boot.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <plat/common/platform.h>
+
+extern char imx7_rotpk_hash[], imx7_rotpk_hash_end[];
+
+int plat_get_rotpk_info(void *cookie, void **key_ptr, unsigned int *key_len,
+			unsigned int *flags)
+{
+	*key_ptr = imx7_rotpk_hash;
+	*key_len = imx7_rotpk_hash_end - imx7_rotpk_hash;
+	*flags = ROTPK_IS_HASH;
+
+	return 0;
+}
+
+int plat_get_nv_ctr(void *cookie, unsigned int *nv_ctr)
+{
+	*nv_ctr = 0;
+
+	return 0;
+}
+
+int plat_set_nv_ctr(void *cookie, unsigned int nv_ctr)
+{
+	return 1;
+}
+
+int plat_get_mbedtls_heap(void **heap_addr, size_t *heap_size)
+{
+	return get_mbedtls_heap_helper(heap_addr, heap_size);
+}