ramips: Fix comment in rt3050 ethernet switch driver.

Line 444 is actually enabling all switch ports by setting the disable bits
to 0. This needs to be done because the bootloader sets all ports to disabled
by default (which is the case for at least one router based on RT5350).

So, this patch fixes the comment in line 443.

Signed-off-by: Vittorio Gambaletta <openwrt@vittgam.net>

SVN-Revision: 49289