use r4k cache code, which does not solve our zombie problem, but minor patches needed...

use r4k cache code, which does not solve our zombie problem, but minor patches needed. broadcom has copied c-mips32.c into c-bcm4710.c and removed code for scache handling. they added some functions I need to add again later. c-mips32.c is obsolete in 2.4.29 and is mostly included in c-r4k.c, which we use now

git-svn-id: svn://svn.openwrt.org/openwrt/trunk/openwrt@321 3c298f89-4303-0410-b956-a3cf2f4a3e73