porting/linux: Fix missing MYNEWT_VAL define
Fixes a regression introduced in Nimble PR
#define MYNEWT_VAL_BLE_L2CAP_COC_MAX_NUM (1)
#endif
+#ifndef MYNEWT_VAL_BLE_L2CAP_COC_MTU
+#define MYNEWT_VAL_BLE_L2CAP_COC_MTU (MYNEWT_VAL_MSYS_1_BLOCK_SIZE - 8)
+#endif
+
#ifndef MYNEWT_VAL_BLE_L2CAP_JOIN_RX_FRAGS
#define MYNEWT_VAL_BLE_L2CAP_JOIN_RX_FRAGS (1)
#endif
