mimxrt/mpconfigport: Enable PPP for boards with lwIP.

PPP is now enabled on all boards with Ethernet support.  PPP could be
enabled for other boards without Ethernet like the Teensy 4.0 as well in a
second step.  Enabling for MIMXRT101x boards is hardly possible due to the
large RAM demand of lwIP.

Tested with a Teensy 4.1 board and a SimCom A7608 GPRS/LTE modem.

Signed-off-by: robert-hh <robert@hammelrath.com>

Author: robert-hh

ports/mimxrt/mpconfigport.h

@@ -139,6 +139,10 @@ uint32_t trng_random_u32(void);
 #define MICROPY_PY_HASHLIB_MD5              (MICROPY_PY_SSL)
 #define MICROPY_PY_HASHLIB_SHA1             (MICROPY_PY_SSL)
 #define MICROPY_PY_CRYPTOLIB                (MICROPY_PY_SSL)
+#ifndef MICROPY_PY_NETWORK_PPP_LWIP
+#define MICROPY_PY_NETWORK_PPP_LWIP         (MICROPY_PY_LWIP)
+#endif
+#define MICROPY_PY_LWIP_PPP                 (MICROPY_PY_NETWORK_PPP_LWIP)
 
 #ifndef MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
 #define MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE (1)