linux-user: fix TARGET_NR_select

linux-user: fix TARGET_NR_select

TARGET_NR_select can have three different implementations:

  1- to always return -ENOSYS

     microblaze, ppc, ppc64

     -> TARGET_WANT_NI_OLD_SELECT

  2- to take parameters from a structure pointed by arg1
    (kernel sys_old_select)

     i386, arm, m68k

     -> TARGET_WANT_OLD_SYS_SELECT

  3- to take parameters from arg[1-5]
     (kernel sys_select)

     x86_64, alpha, s390x,
     cris, sparc, sparc64

Some (new) architectures don't define NR_select,

  4- but only NR__newselect with sys_select:

      mips, mips64, sh

  5- don't define NR__newselect, and use pselect6 syscall:

      aarch64, openrisc, tilegx, unicore32

Reported-by: Timothy Pearson <tpearson@raptorengineering.com>
Reported-by: Allan Wirth <awirth@akamai.com>
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>