proc: uninline proc_create()

Save some code from ~320 invocations all clearing last argument.

	add/remove: 3/0 grow/shrink: 0/158 up/down: 45/-702 (-657)
	function                                     old     new   delta
	proc_create                                    -      17     +17
	__ksymtab_proc_create                          -      16     +16
	__kstrtab_proc_create                          -      12     +12
	yam_init_driver                              301     298      -3

		...

	cifs_proc_init                               249     228     -21
	via_fb_pci_probe                            2304    2280     -24

Link: http://lkml.kernel.org/r/20170819094702.GA27864@avx2


Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>