fix build regression in i386 asm for atan2, atan2f

commit f3ed8bfe8a82af1870ddc8696ed4cc1d5aa6b441 inadvertently removed
labels that were still needed.

src/math/i386/atan2.s

@@ -11,4 +11,4 @@ atan2:
 	jae 1f
 		# subnormal x, return x with underflow
 	fsts 4(%esp)
-	ret
+1:	ret

src/math/i386/atan2f.s

@@ -13,4 +13,4 @@ atan2f:
 	fld %st(0)
 	fmul %st(1)
 	fstps 4(%esp)
-	ret
+1:	ret