at91: Update meesc board to new SoC access * convert meesc board to use c stucture SoC access * change gpio access to at91_gpio syntax * moved CONFIG_SYS_HZ below board and cpu defines (purely cosmetic) Signed-off-by: Daniel Gorsulowski <Daniel.Gorsulowski@esd.eu> Signed-off-by: Reinhard Meyer <u-boot@emk-elektronik.de>