1. Porting the 3A+690E x86emu module to 2G+690e platform and it works
correctly.
2. The HT frequency is adjusted to 800MHz.
3. The start address of PCI IO and memory space are adjusted according
to the 3A+690E platform.
4. The framebuffer address(0xb0000000) doesn't map through TLB. The
pcitlb.c is added in start.S, but it doesn't work.
5. Fix the IO-read/write base from 0xa000_0000 to 0x0000_0000 in
sys/linux/io.h.
LI Wengang