include/asm-m32r/thread_info.h: kmalloc + memset conversion to kzalloc

Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>