Merge 625d3449 ("Revert "kernel/printk: add kmsg SEEK_CUR handling"") into android-mainline

Can cause known issues, so good to get merged into the tree now.

Change-Id: If71170a490cf833a4db4d730f76ceda10cfe19ed
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>