net/9p: change net/9p module name to 9pnet

Change module name of net/9p module from 9p.ko to 9pnet.ko. fs/9p module
already uses 9p.ko name.
Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>

net/9p/Makefile

-obj-$(CONFIG_NET_9P) := 9p.o
+obj-$(CONFIG_NET_9P) := 9pnet.o
 
-9p-objs := \
+9pnet-objs := \
 	mod.o \
 	trans_fd.o \
 	mux.o \
@@ -10,4 +10,4 @@ obj-$(CONFIG_NET_9P) := 9p.o
 	fcprint.o \
 	util.o \
 
-9p-$(CONFIG_SYSCTL) += sysctl.o
+9pnet-$(CONFIG_SYSCTL) += sysctl.o