OpenRISC updates for 6.15

This is a bit late as I was on holiday, but as there are no huge
structural changes I hope it's OK to include mid release cycle.

 - Support for cacheinfo API to expose OpenRISC cache info via sysfs,
   this also translated to some cleanups to OpenRISC cache flush and
   invalidate API's
 - Documentation updates for new mailing list and toolchain binaries

OpenRISC patches for 4.14

Just one thing here:
 - Fix warning for upcoming work to remove linux/vmalloc.h from
   asm-generic/io.h

Linux 3.19-rc6

Linux 3.19-rc5

linux 3.19-rc4

Linux 3.19-rc3

Linux 3.19-rc2

Linux 3.19-rc1

Linux 3.18

Linux 3.18-rc7