realtek: SMP handling of R4K timer interrupts

realtek: SMP handling of R4K timer interrupts

Until now there has been no good explanation why we mess with the R4K
timer on SMP. After extensive testing and looking at the SDK code it
becomes clear what it is all about.

When we disable the CEVT_R4K module (we will do with the new timer
driver) the R4K timer hardware still fires interrupts on the secondary
CPU. To get around this we have two options:

- Disable IRQ 7
- Stop the counter completely

This patch selects option two because this is the root of evil.. To be
on the safe side we will do it only in case the CEVT_R4K module is
disabled.

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>