hwclock: use symbolic magic values passed in between functions

hwclock: use symbolic magic values passed in between functions

The manipulate_clock() is seeing return value from
busywait_for_rtc_clock_tick().

And the get_permissions_cmos() can see i386_iopl() return value.

Reviewed-by: J William Piggott <elseifthen@gmx.com>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>