MIPS: cevt-r4k: Don't call get_c0_compare_int if timer irq is installed

In the Linux kernel, the following vulnerability has been resolved: MIPS: cevt-r4k: Don't call get_c0_compare_int if timer irq is installed This avoids warning: [ 0.118053] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:283 Caused by get_c0_compare_int on secondary CPU. We also skipped saving IRQ number to struct clock_event_device *cd as it's never used by clockevent core, as per comments it's only meant for "non CPU local devices".