staging: hv: Fix Kconfig dependency of hv_blkvsc

LBDAF is not available nor necessary on 64BIT kernel. This patch
fixed the dependency for hv_blkvsc module on 64BIT kernel.
Thanks vrataj2 [vrataj2@comcast.net] for reporting this problem.

Reported-by: vrataj2 <vrataj2@comcast.net>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>