gta02: Set pcf50633 charger_reference_current_ma

This value is board-specific and is needed for calculations to set
charging current limit properly.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Nelson Castillo <arhuaco@freaks-unidos.net>
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>