wireless-regdb: update US' regulatory rules

This:

  o Increases the max EIRP on the 2.4 GHz band from
    27 dBm to 30 dBm

  o Decreases the max EIRP for the first DFS frequency
    range by 1 dBm

  o Removes the two lower 5 GHz DFS frequency ranges

Source is QCA's regulatory team's efforts.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>