clone: save clone flags unconditionally

This simplifies the code a bit - at the expense of 1 insn

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
clone to set TP if CLONE_SETTLS

Typically kernel would set the TP register of newly created thread in
clone syscall with CLONE_SETTLS.

However this implies that:
* kernel knows of the exact TP register (which is already different for
  ARCompact and ARCv2) and is a detail which becomes part of the ABI
* kernel also needs to handle the unlikely but possible case of !TLS
  userspace (e.g. Android libc) case where TP reg is not reserved and
  thus need not be mucked with (using ELF personality based detection)

It is better to confine this detail to userspace runtime and set TP reg
right after clone syscall returns.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>