gdb/sparc: Use default_unwind_pc

Make use of the default gdbarch method gdbarch_unwind_pc where
possible.

I have not tested this change but, by inspecting the code, I believe
the default methods are equivalent to the code being deleted.

gdb/ChangeLog:

	* sparc-tdep.c (sparc_unwind_pc): Delete.
	(sparc32_gdbarch_init): Don't register deleted function with
	gdbarch.
2 files changed