tags: Use $SRCARCH
tags: Use $SRCARCH

$ make mrproper
$ make tags
  GEN     tags
  find: `arch/x86_64/': No such file or directory

Caused by commit f81b1be (tags: include headers before source files)

Cc: Guennadi Liakhovetski <50875182aae23d69ca7738697596f18a14e926fc@gmx.de>
Acked-by: WANG Cong <0f114804888b88d50037b04b42e57b858d851b87@gmail.com>
Signed-off-by: Michal Marek <0c835876a532a476f30fdb1f6e963bae6c5a1a04@suse.cz>

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