From: Ralf Baechle <ralf@linux-mips.org>

 - Kconfig cleanups:
    - enable DMA_NONCOHERENT, DMA_COHERENT or DMA_IP27 via reverse dependencies
    - untangle VRC4171 / VRC4173 selection
    - R10000 support enables PREFETCH
    - SEAD needs IRQ_CPU
 - Update defconfig against latest Kconfig files.
 - Fix computation of return address if syscall number was out of range
 - Add power managment hooks in signal code.
 - Don't try to handle signals when previous context was not in user mode.
 - Fix serial interface setup for VR41xx systems.
 - Build fixes after CLEAR_BITMAP changed name.
 - Removes bogus comment from <asm/checksum.h>
 - <asm/hdreg.h> is dead.
 - Start collecting common definitions for PMON firmware in <asm/pmon.h>
 - Define ARCH_MIN_TASKALIGN to 8; we have 64-bit members even on 32-bit
   kernels if we're running on MIPS II or better.