MIPS: mm: remove comment referring to removed CONFIG_MIPS_CMP

CMP support was removed in commit 7fb6f7b0af ("MIPS: Remove
deprecated CONFIG_MIPS_CMP"), but a comment referring to it remained in
arch/mips/mm/c-r4k.c. Remove it.

Discovered while searching for CONFIG_* symbols referenced in code but
not defined in any Kconfig file.

Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/mm/c-r4k.c

@@ -1757,11 +1757,6 @@ void r4k_cache_init(void)
 	build_clear_page();
 	build_copy_page();
 
-	/*
-	 * We want to run CMP kernels on core with and without coherent
-	 * caches. Therefore, do not use CONFIG_MIPS_CMP to decide whether
-	 * or not to flush caches.
-	 */
 	local_r4k___flush_cache_all(NULL);
 
 	coherency_setup();