lib: cordic: add library module providing cordic angle calculation

The brcm80211 driver in the staging tree has a cordic function to
determine cosine and sine for a given angle. Feedback received from
John Linville suggested that these kind of functions should be made
available to others as a library function in the kernel tree. The
b43 driver also has a cordic angle calculation implemented.

Cc: linux-kernel@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>