* mn10300-tdep.c (mn10300_pop_frame): Split the mn10300-specific

* mn10300-tdep.c (mn10300_pop_frame): Split the mn10300-specific
stuff out into mn10300_pop_frame_regular, and use
generic_pop_current_frame.  This lets us share code, and also
makes this function's prototype match that expected by gdbarch.
Make this function static.
(mn10300_pop_frame_regular): New function.
(mn10300_gdbarch_init): Register mn10300_pop_frame as the
gdbarch's pop_frame method.
* config/mn10300/tm-mn10300.h (POP_FRAME): Delete definition.
(mn10300_pop_frame): Delete declaration.