blktrace: remove the big kernel lock
blktrace: remove the big kernel lock

According to Jens, this code does not need the BKL at all,
it is sufficiently serialized by bd_mutex.

Signed-off-by: Arnd Bergmann <f2c659f01951776204a6c5b902787d9019fbeebd@arndb.de>
Cc: Jens Axboe <08e836a620179c237f631ad0545a7ebdf54201f3@fusionio.com>
Cc: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs