sparc32: Enable the relocation target R_SPARC_DISP32 for sparc32

GNU Binutils 2.20.1 generates .eh_frame sections that uses R_SPARC_DISP32.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>