Remove unused defines from code which should help
in easy reading of code.

Also, use the opportuinity to keep the SPIGCR1
register defines together.
Tested-By: NMichael Williamson <michael.williamson@criticallink.com>
Tested-By: NBrian Niebuhr <bniebuhr@efjohnson.com>
Signed-off-by: NSekhar Nori <nsekhar@ti.com>