x86: Don't use address override with segment regsiter

x86: Don't use address override with segment regsiter

Address override only applies to the (reg32) part in the thread address
fs:(reg32).  Don't rewrite thread address like

(set (reg:CCZ 17 flags)
    (compare:CCZ (reg:SI 98 [ __gmpfr_emax.0_1 ])
        (mem/c:SI (plus:SI (plus:SI (unspec:SI [
                            (const_int 0 [0])
                        ] UNSPEC_TP)
                    (reg:SI 107))
                (const:SI (unspec:SI [
                            (symbol_ref:SI ("previous_emax") [flags 0x1a] <var_decl 0x7fffe9a11cf0 previous_emax>)
                        ] UNSPEC_DTPOFF))) [1 previous_emax+0 S4 A32])))

if address override is used to avoid the invalid memory operand like

	cmpl	%fs:previous_emax@dtpoff(%eax), %r12d

gcc/

	PR target/116839
	* config/i386/i386.cc (ix86_rewrite_tls_address_1): Make it
	static.  Return if TLS address is thread register plus an integer
	register.

gcc/testsuite/

	PR target/116839
	* gcc.target/i386/pr116839.c: New file.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>