[Patch] console: limit the range of VGACON_SOFT_SCROLLBACK_SIZE

[Amerigo Wang <amwang@redhat.com>]

BuraphaLinux reported that we will trigger a mm warning when
we CONFIG_VGACON_SOFT_SCROLLBACK_SIZE=65536, this is because
mm cann't allocate so many pages. We should limit the range
of CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, don't give a user
any chance to trigger that.

Reported-by: BuraphaLinux Server <buraphalinuxserver@gmail.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: David S. Miller <davem@davemloft.net>

---
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index fc7d9bb..8e8f18d 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -37,6 +37,7 @@ config VGACON_SOFT_SCROLLBACK
 config VGACON_SOFT_SCROLLBACK_SIZE
        int "Scrollback Buffer Size (in KB)"
        depends on VGACON_SOFT_SCROLLBACK
+       range 1 1024
        default "64"
        help
          Enter the amount of System RAM to allocate for the scrollback