alpha: remove dead BIO_VMERGE_BOUNDARY
alpha: remove dead BIO_VMERGE_BOUNDARY

The block layer dropped the virtual merge feature
(b8b3e16cfe6435d961f6aaebcfd52a1ff2a988c5). BIO_VMERGE_BOUNDARY
definition is meaningless now.

Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>
Cc: Richard Henderson <aea4fd857e97ee7d33f60175ba9388a955b9d916@twiddle.net>
Cc: Ivan Kokshaysky <ec437ab60af367f0fec0f6a3cd47f9cbad7b487f@jurassic.park.msu.ru>
Signed-off-by: Jens Axboe <165ab144a3ccfd9429d5c6466b275f24fafdb114@oracle.com>

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