use zephyr tincybor instead of mcuboot build-in tinycbor

Zephyr has build-in tinycbor code of version which doesn't
require newlib-c by default. Also the cborattr module is now
taken form the zephyr code.

This patch decrease flash consumption by 10 KB for serial recovery build.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
diff --git a/boot/boot_serial/src/boot_serial.c b/boot/boot_serial/src/boot_serial.c
index 7467c9f..e23040c 100644
--- a/boot/boot_serial/src/boot_serial.c
+++ b/boot/boot_serial/src/boot_serial.c
@@ -35,6 +35,7 @@
 #include <crc16.h>
 #include <serial_adapter/serial_adapter.h>
 #include <base64.h>
+#include <cbor.h>
 #else
 #include <bsp/bsp.h>
 #include <hal/hal_system.h>
@@ -43,10 +44,10 @@
 #include <console/console.h>
 #include <crc/crc16.h>
 #include <base64/base64.h>
-#endif /* __ZEPHYR__ */
-
 #include <tinycbor/cbor.h>
 #include <tinycbor/cbor_buf_reader.h>
+#endif /* __ZEPHYR__ */
+
 #include <cborattr/cborattr.h>
 
 #include <flash_map/flash_map.h>
@@ -216,7 +217,11 @@
 
     memset(img_data, 0, sizeof(img_data));
     cbor_buf_reader_init(&reader, (uint8_t *)buf, len);
+#ifdef __ZEPHYR__
+    cbor_parser_cust_reader_init(&reader.r, 0, &parser, &value);
+#else
     cbor_parser_init(&reader.r, 0, &parser, &value);
+#endif
     rc = cbor_read_object(&value, attr);
     if (rc || off == UINT_MAX) {
         rc = MGMT_ERR_EINVAL;
@@ -326,7 +331,11 @@
     buf += sizeof(*hdr);
     len -= sizeof(*hdr);
     bs_writer.bytes_written = 0;
+#ifdef __ZEPHYR__
+    cbor_encoder_cust_writer_init(&bs_root, &bs_writer, 0);
+#else
     cbor_encoder_init(&bs_root, &bs_writer, 0);
+#endif
 
     /*
      * Limited support for commands.