Soft I2C

That is Edited version of Original version for stm32

精简了部分代码，增加8/16bit寄存器地址的突发（连续）读写函数

移植到展锐8850平台

Name		Name	Last commit message	Last commit date
Latest commit History 15 Commits
readme.md		readme.md
sw_i2c.c		sw_i2c.c
sw_i2c.h		sw_i2c.h
sw_i2c_port_stm32.c		sw_i2c_port_stm32.c
sw_i2c_port_unisoc_8850.c		sw_i2c_port_unisoc_8850.c

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