or1k-tdep: add set_gdbarch_adjust_breakpoint_address

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
or1k-tdec: Add a check for NULL ptr in or1k_skip_prologue

* or1k-tdep.c (or1k_skip_prologue): Add a check for NULL
	pointer while comparing debugformat to "dwarf".

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>