Rework the simulators button reading to not implement it's own complete driver.

Instead, implement it more as a target driver with button_read_device(), button_init_device() and button_hold(), then use the normal button driver from firmware/drivers/button.c.
Fixes FS#10451 ("backlight off on hold doesn't function properly").

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22799 a1c6a512-1295-4272-9138-f99709370657
3 files changed