sparc64: uaccess_64 macro whitespace fixes

Macros within arch/sparc/include/asm/uaccess_64.h are made harder to
read because they violate a bunch of coding style rules.

Fix it up.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>