Fix and update for gcc-4.0.

- arch/m32r/kernel/signal.c:
  Change type of the 8th parameter of sys_rt_sigsuspend() from
  'struct pt_regs' to 'struct pt_regs *'.
  This functions make use of the 'regs' parameter to return status value,
  but gcc-4.0 optimizes and removes it as a dead code.
  Functions, sys_sigaltstack() and sys_rt_sigreturn(), have also modified.

- arch/m32r/lib/usercopy.c, include/asm-m32r/uaccess.h:
  Add early-clobber constraints('&') to output values of asm statements;
  these constraints seems to be required for gcc-4.0 register assignment.
Signed-off-by: Hayato Fujiwara <fujiwara@linux-m32r.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>