This patch adds a MMU dependency to configure the ZSMALLOC in
drivers/staging/zsmalloc/Kconfig. Without this patch, build
system can lead to build failure. This was observed during
randconfig testing, in which ZSMALLOC was enabled w/o MMU being
enabled. Following was the error:
LD vmlinux
drivers/built-in.o: In function `__zs_map_object':
drivers/staging/zsmalloc/zsmalloc-main.c:650: undefined reference to `map_vm_area'
make: *** [vmlinux] Error 1