xen: remove XEN_SCRUB_PAGES in xen.config

Commit 197ecb3802c0 ("xen/balloon: add runtime control for scrubbing
ballooned out pages") changed config XEN_SCRUB_PAGES to config
XEN_SCRUB_PAGES_DEFAULT. As xen.config sets 'XEN_BALLOON=y' and
XEN_SCRUB_PAGES_DEFAULT defaults to yes, there is no further need to set
this config in the xen.config file.

Remove setting XEN_SCRUB_PAGES in xen.config, which is without
effect since the commit above anyway.

Signed-off-by: Lukas Bulwahn <[e-mail]>
Reviewed-by: Juergen Gross <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Juergen Gross <[e-mail]>

kernel/configs/xen.config

···
 CONFIG_XEN_SCSI_FRONTEND=m
 # others
 CONFIG_XEN_BALLOON=y
-CONFIG_XEN_SCRUB_PAGES=y
 CONFIG_XEN_DEV_EVTCHN=m
 CONFIG_XEN_BLKDEV_FRONTEND=m
 CONFIG_XEN_NETDEV_FRONTEND=m