nvram: Drop the bkl from nvram_llseek()

There is nothing to protect inside nvram_llseek(), the file
offset doesn't need to be protected and nvram_len is only
initialized from an __init path.

It's safe to remove the big kernel lock there.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1255116030-6929-1-git-send-email-fweisbec@gmail.com>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>