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.

pull rt-thread master

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

[Drivers] re-write serial framework.

[Kernel] src/timer: fix a compile warning

Next ymodem

[bsp] add the linker script file.

Frequent 'C' on the handshake will confuse some sender(lrzsz for
example).

Make fast path fast and slow path slow.

[bsp] add the lpc43xx bsp support.

2. Fix data transfer size calculate error issue;