sparc: refactor code in fault_32.c

The sparc allmodconfig build broke due to enabling of the
branch_tracer that does some very clever things with
all if conditions. This caused my gcc 3.4.5 to be so confused that
it emitted a warning:

arch/sparc/mm/fault_32.c: In function `do_sparc_fault':
arch/sparc/mm/fault_32.c:176: warning: 'fixup' might be used uninitialized in this function

And with -Werror this broke the build.

Refactor code so it:
1) becomes more readable
2) no longer emit a warning with the branch_tracer enabled
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/mm/fault_32.c

@@ -283,7 +283,8 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
 	/* Is this in ex_table? */
 no_context:
 	g2 = regs->u_regs[UREG_G2];
-	if (!from_user && (fixup = search_extables_range(regs->pc, &g2))) {
+	if (!from_user) {
+		fixup = search_extables_range(regs->pc, &g2);
 		if (fixup > 10) { /* Values below are reserved for other things */
 			extern const unsigned __memset_start[];
 			extern const unsigned __memset_end[];