arm: parasite: implement arch_get_tls() in C

This patch should simplify the routine interface change
in the following patch.

Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Reviewed-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
arm: prepare syscall table generation scripts to be shared with AArch64

Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com
Reviewed-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>