staging: Remove Netlogic XLP network driver

staging: Remove Netlogic XLP network driver

The Netlogic XLP platform was removed in commit 95b8a5e0111a ("MIPS:
Remove NETLOGIC support"), so this driver is now dead.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ganesan Ramalingam <ganesanr@broadcom.com>
Cc: Jayachandran Chandrashekaran Nair <jchandra@broadcom.com>
Cc: linux-staging@lists.linux.dev
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211109161401.2204280-1-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>