gas/dw2gencfi: correct .sframe section conditional

gas/dw2gencfi: correct .sframe section conditional

While originally this was in preparation of a subsequent change making
SUPPORT_FRAME_LINKONCE potentially dependent on a global variable, the
construct appears unlikely to have been correct in the first place: The
variable would have been passed reliably uninitialized when
SUPPORT_FRAME_LINKONCE is build-time true.

While there correct indentation of the parameters passed to
get_cfi_seg().