cpu/esp32: Fixes the maximum packet size of 255 bytes in the esp_eth netdev driver of ESP32 mcu.

Fixes the maximum packet size of 255 bytes in the esp_eth netdev driver of ESP32 mcu.

fixup! cpu/esp32: fixes esp_net maximum packet size

cortexm_common: add FPU support for cortex-m4f and cortex-m7

pkg: gecko_sdk: bump version + vendor headers

 netopt: provide option to (de-)activate 6Lo

tests/periph_uart: fix baudrate truncation

net/nanocoap: allow user to configure macros

net/coap: allow user to configure message retry macros

Since some boards an int is 16 bits the atoi truncates values.
This commit using a long instead of an int.

net/gcoap: add config macros to config doc group

tests/driver_ds1307: Blacklist iotlab boards

This states iotlab boards shouldn't run these tests.
This is because the i2c address of L3G4200 is the same ad the ds1307.
This causes an error that thinks the test is valid when it is not.

boards/common: change openocd config file for stm32l1x

cpu/nrf5x: move periph_gpio/periph_gpio_irq at an even more common level

tests/sx127x: set b-l072z-lrwan1 as default board

loramac: change rxdelay1 to millisec, was seconds

net/nanocoap: remove obsolete macro

 gnrc_ipv6_ext_rh: add ICMPv6 error message sending

boards/nucleo-f767zi: use common STM32 i2c configuration

drivers/bh1750: Fix mislabeled i2c address

boards/nucleo-f072rb: configure I2C using common stm32 configuration

The i2c address when the pin is high/low are swapped.
This swaps them to match the datasheet and changes the default to low.

boards/stm32: remove useless empty conf defines