Update JEDEC information for lower density of W25Q series.

0x4011 - 1 Mb
0x4012 - 2 Mb
0x4013 - 4 Mb
0x4014 - 8 Mb
0x4015 - 16 Mb
0x4016 - 32 Mb
0x4017 - 64 Mb
0x4018 - 128 Mb
Merge pull request #18 from rogerhu/w25q_jedec

Update JEDEC information for lower density of W25Q series.