[media] dvb_usb_v2: rename module dvb_usbv2 => dvb_usb_v2

I think it is better name. At that phase renaming is quite painless
as module is not yet merged to mainline Kernel.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/dvb-usb-v2/Makefile

-dvb_usbv2-objs := dvb_usb_core.o dvb_usb_urb.o usb_urb.o
-obj-$(CONFIG_DVB_USB_V2) += dvb_usbv2.o
+dvb_usb_v2-objs := dvb_usb_core.o dvb_usb_urb.o usb_urb.o
+obj-$(CONFIG_DVB_USB_V2) += dvb_usb_v2.o
 
 dvb_usb_cypress_firmware-objs := cypress_firmware.o
 obj-$(CONFIG_DVB_USB_CYPRESS_FIRMWARE) += dvb_usb_cypress_firmware.o