drivers: staging: media: easycap: easycap_ioctl: Include version.h header

The output of "make versioncheck" told us that:

drivers/staging/media/easycap/easycap_ioctl.c: 2442: need
linux/version.h

If we take a look at the code, we will see the macro KERNEL_VERSION be
used. So, we need this include.

Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <linux-media@vger.kernel.org>
Cc: <devel@driverdev.osuosl.org >
Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>