Staging: hv: fix spaces coding style issue in vstorage.h

This is a patch to the vstorage.h file that fixed up a TAB and spaces
Errors found by the checkpatch.pl tools, like
spaces required around that ':' (ctx:VxV)

Signed-off-by: Ruslan Pisarev <ruslan@rpisarev.org.ua>
Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>