Remove unneeded version.h includes (and add where needed) for drivers/staging/easycap/

It was pointed out by 'make versioncheck' that linux/version.h was not
always being included where needed and sometimes included needlessly
in drivers/staging/easycap/.
This patch fixes up the includes.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>