qlcnic: Don't use kzalloc unncecessarily for allocating large chunk of memory

Driver allocates a large chunk of temporary buffer using kzalloc
to copy FW image. As there is no real need of this memory to be
physically contiguous, use vzalloc instead.

Signed-off-by: Shahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>