hyperv: Remove the spurious null directive line

The file contains a line that consists of the lone # symbol
followed by a newline. While that is a valid syntax as
defined by the C99+ grammar (6.10.7 "Null directive"), it
serves no apparent purpose in this case.

Remove the null preprocessor directive. No functional changes.

Fixes: e68bda71a238 ("hyperv: Add new Hyper-V headers in include/hyperv")
Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Easwar Hariharan <easwar.hariharan@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>