remove set_fs for riscv

[Christoph Hellwig]

Hi all,

this series converts riscv to the new set_fs less world and is on top of this
branch:

    https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git/log/?h=base.set_fs

The first four patches are general improvements and enablement for all nommu
ports, and might make sense to merge through the above base branch.

Diffstat
 arch/riscv/Kconfig                   |    2 
 arch/riscv/include/asm/thread_info.h |    6 -
 arch/riscv/include/asm/uaccess.h     |  177 +++++++++++++++++------------------
 arch/riscv/kernel/process.c          |    1 
 arch/riscv/lib/Makefile              |    2 
 include/asm-generic/uaccess.h        |   42 +++++---
 include/linux/uaccess.h              |    4 
 7 files changed, 127 insertions(+), 107 deletions(-)