[update] Removed C++ global constructor initialization, this method is not used in GCC4.7 and later versions.

* 为spi添加超时检测,避免卡死。提取公共部份，避免代码复制。

* [gcc][armcc][armclang] rtconfig.CROSS_TOOL->rtconfig.PLATFORM

* [stm32f401-nucleo] arduino support
* 增加application arduino main文件
* 调整目录结构

* Microchip SAM MCU BSP update and add ethernet driver

1. Update Microchip SAM MCU BSP, add I2C, GMAC, ADC driver support. 2. Add ethernet driver support of SAM MCU for RT-Thread.

* Add GMAC and I2C driver support

1. Update MCU BSP to support I2C/ADC/GMAC peripherals. 2. Add I2C and ethernet driver and LWIP support. 3. Update serial driver.

* Add I2C driver and move some files to the common folder

1. Add I2C driver. 2. Move the same drivers and demo code to same folder to reduce duplicated code.

* rt1052 添加 RT-Thread Studio 工程

[stm32f072] support Arduino I2C and update readme

- add comments
- remove ARDUINO_PWM_HZ
- remove initVariant blank function
- support DAC0
- improve Kconfig of STM32L475 PANDORA
- add readme
- add i2c1 bus device

Co-authored-by: NWayne Lin <wclin@nuvoton.com>

* Update ipc.c

Parameter name standardization
Co-authored-by: NStanley <stanleylwinn@gmail.com>

[update] RT-Thread Robot automatic submission

删除多余注释，另外确定了对于其他型号单片机的适应性