Staging: hv: rename hyperv_utils.c to hv_utils.c

As the module only has one .c file in it, just name the file
the same as the desired module.

Cc: Hank Janssen <hjanssen@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>