rs6000: Fix for separate shrink-wrapping for fp (PR80860, PR80843)

After my r248256, rs6000_components_for_bb allocates an sbitmap of size
only 32 while it can use up to 64.  This patch fixes it.  It moves the
n_components variable into the machine_function struct so that other
hooks can use it.


	PR bootstrap/80860
	PR bootstrap/80843
	* config/rs6000/rs6000.c (struct machine_function): Add new field
	n_components.
	(rs6000_get_separate_components): Init that field, use it.
	(rs6000_components_for_bb): Use the field.

From-SVN: r248421