staging: brcm80211: resolved checkpatch warnings in N phy

Code that exceeded the 80 char limit has been placed in separate
functions. Checkpatch warnings for the phy dir are now reduced to 1.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>