Fix bootstrap pull-up/pull-down resistance on rev2 PCB

[gardners]

Some of the bootstrap lines are marginal, in particular, the one that controls whether the Atheros 9331 boots from its internal ROM (wrong) or serial flash (correct).

We added a 2K resister in parallel to the existing resistor to fix this problem. This suggests that the current pull-up/down resistors for the bootstraps should be reduced to around this size.

[gardners]

The WR703N used 10K resisters, rather than the 49K resisters on the rev2 PCB (http://squonk42.github.io/TL-WR703N/). We should therefore move to 10K resisters for all of these.