MAINTAINERS: Remove Jeremy from the Xen subsystem.

Jeremy has been a key person in making Linux work with Xen.
He has been enjoying the last year working on something
different so reflect that in the maintainers file.

CC: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>

CREDITS

@@ -1120,6 +1120,7 @@ D: author of userfs filesystem
 D: Improved mmap and munmap handling
 D: General mm minor tidyups
 D: autofs v4 maintainer
+D: Xen subsystem
 S: 987 Alabama St
 S: San Francisco
 S: CA, 94110