of: Add vendor prefix 'netlogic'

Add vendor name "netlogic" in vendor-prefixes.txt, which will be used for
the Netlogic XLP and XLPII MIPS SoCs. These processors were from NetLogic
Microsystems that is now a part of Broadcom Corporation.

Signed-off-by: Subhendu Sekhar Behera <sbehera@broadcom.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>