MIPS: Remove usage of CEVT_R4K_LIB config option.

Manuel Lauss <manuel.lauss@gmail.com> writes:

I introduced it as a fallback because early revisions of Alchemy hardware
we shipped had a non-functional 32kHz timer and had to rely on the r4k
timer instead.  Previously the r4k timer was initialized regardless, but
it's useless with the "wait" instruction.

So long story short:   I need either the on-chip 32kHz timer OR the r4k
timer if the 32kHz one is unusable, but not both, and r4k timer is useless
when au1k_idle is in use.

The current in-kernel Alchemy boards all work with the 32kHz timer, so I'm
not against removing R4K_LIB symbols.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/time.h

@@ -50,10 +50,8 @@ extern int (*perf_irq)(void);
 /*
  * Initialize the calling CPU's compare interrupt as clockevent device
  */
-#ifdef CONFIG_CEVT_R4K_LIB
 extern unsigned int __weak get_c0_compare_int(void);
 extern int r4k_clockevent_init(void);
-#endif
 
 static inline int mips_clockevent_init(void)
 {