Refactor gdbarch method print_float_info

Refactor gdbarch method print_float_info

This patch is to change print_float_info gdbarch method for the
following two reasons,

 1. we want to add a default implementation of print_float_info to
    dump the float pointer registers.  It can be reused by backend to
    print something more than float point registers.
 2. we want to simplify the caller of print_float_info,
    infcmd.c:print_float_info.

gdb:

2014-12-18  Yao Qi  <yao@codesourcery.com>

 	* gdbarch.sh (print_float_info): Change its type from 'M' to 'm'.
	* gdbarch.c: Re-generated.
	* gdbarch.h: Likewise.
	* infcmd.c (default_print_float_info): New function.
	(print_float_info): Removed.  Move code to
	default_print_float_info.
	(float_info): Adjust to call gdbarch_print_float_info.
	* inferior.h (default_print_float_info): Declare it.