ARM: pxa: magician: Fix and add charging detection functions

This patch fixes the charging detection functions for pda_power driver
(according to newly discovered EGPIOs) and add NiCd backup accumulator
charging support.

Signed-off-by: Petr Cvek <petr.cvek@tul.cz>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>