vme_user: Update API to work in mixed environments

This patch updates the vme_master and vme_slave structures to use
types with well defined size and to prevent the compiler from
inserting padding (between enable and vme_addr for one).

The original vme_master and vme_slave structs would be different
sizes and have different layouts depending on whether they were built
for a 32-bit or 64-bit system.

On x86 it is possible to have a 32-bit userspace and a 64-bit kernel.
In this type of environment, the userspace and kernel vme_user APIs
would disagree and prevent ioctls from executing (based on ioctl
signatures from _IOR and _IOW).

Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Acked-by: Martyn Welch <martyn.welch@ge.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>