drvers->drivers

1. Resize RT_LWIP_SEG_NUM drom 8 to 12
2. modify gcc compile switch, using C99

1. Add ETH MAC driver using DMA for Tx and Rx lwip pBuf.
2. Modify the tivaware emac library to fix the bug that PHY read is not stable when sysclk is 120MHz
3. In PHY IRQ handler, insert a dummy reading (REG_BMSR) before read PHY_STS to force update STS register.

This reverts commit 666d1298.

1. Add ETH MAC driver using DMA for Tx and Rx lwip pBuf.
2. Modify the tivaware emac library to fix the bug that PHY read is not stable when sysclk is 120MHz
3. In PHY IRQ handler, insert a dummy reading (REG_BMSR) before read PHY_STS to force update STS register.

[bsp] modify the uart_driver to fit the new rt-thread serial device driver framework. Modify the template.uvproj for auto generate MDK project.