net/rose: Use GFP_ATOMIC

The other calls to kmalloc in the same function use GFP_ATOMIC, and indeed
two locks are held within the body of the function.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/

)

// <smpl>
@@ identifier f; @@

*f(...,GFP_ATOMIC,...)
... when != spin_unlock(...)
    when != read_unlock(...)
    when != write_unlock(...)
    when != read_unlock_irq(...)
    when != write_unlock_irq(...)
    when != read_unlock_irqrestore(...)
    when != write_unlock_irqrestore(...)
    when != spin_unlock_irq(...)
    when != spin_unlock_irqrestore(...)
*f(...,GFP_KERNEL,...)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>