Build failure on next-20190424

[Corentin Labbe <clabbe.montjoie@xxxxxxxxx>]

Hello

On next-20190424, I hit the following build failure:
arch/sparc/kernel/ds.c: In function 'ldom_set_var':
arch/sparc/kernel/ds.c:799:3: error: 'strcpy': writing at least 1 byte into a region of size 0 overflows the destination [-Werror=stringop-overflow=]

Regards