staging: rtl8723bs: Use vsnprintf extensions %pM and %pI4

Convert the uses of MAC_FMT, MAC_ARG and IP_FMT, IP_ARG to the
kernel extensions.

This could eventually be improved with an in-place substitution.

This reduces object code size a bit too.

$ size drivers/staging/rtl8723bs/r8723bs.o*
   text	   data	    bss	    dec	    hex	filename
 672812	  27040	  24232	 724084	  b0c74	drivers/staging/rtl8723bs/r8723bs.o.allyesconfig.new
 676299	  27040	  24232	 727571	  b1a13	drivers/staging/rtl8723bs/r8723bs.o.allyesconfig.old
 430398	  27040	  21528	 478966	  74ef6	drivers/staging/rtl8723bs/r8723bs.o.defconfig.new
 431581	  27040	  21528	 480149	  75395	drivers/staging/rtl8723bs/r8723bs.o.defconfig.old

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>