tile: add null check for kzalloc in tile/kernel/setup.c

Should check the return value of kzalloc first to avoid the null pointer.
Then can dereference the non-null pointer to access the fields of struct
resource.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>