Please give-back lyx-1.5.4-2 on mips and powerpc

[Sven Hoexter <sven@timegate.de>]

Hi,
would be cool if someone could give-back lyx-1.5.4-2 on mips and powerpc so that
lyx can hopefully migrate to testing in the next days.

Currently users of Lenny are hit by #475523 after Qt 4.4 migrated to testing.

Thanks,
Sven