Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Provide a means for UV interrupt MMRs to be setup with the message to be sent
when an MSI is raised.
Signed-off-by: NDean Nelson <dcn@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>