alpha: fix build after vmlinux.lds.S cleanup
alpha: fix build after vmlinux.lds.S cleanup

Add include to get missing THREAD_SIZE definition

Signed-off-by: Sam Ravnborg <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@ravnborg.org>
Cc: Tim Abbott <d0224c9164b19e926c250294e7a569c6d5ad5163@ksplice.com>
Cc: Ivan Kokshaysky <ec437ab60af367f0fec0f6a3cd47f9cbad7b487f@jurassic.park.msu.ru>
Cc: Richard Henderson <aea4fd857e97ee7d33f60175ba9388a955b9d916@twiddle.net>

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