Staging: irda: Use !x instead of NULL comparison

Test for NULL as !x where functions that return NULL on failure
are used. Done using the following semantic patch by coccinelle.

@ is_null @
expression E;
statement S;
@@

E = (\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|
usb_alloc_urb\|alloc_netdev\|dev_alloc_skb\)(...));

(
if(!E)
   S
|
-if(E==NULL)
+if(!E)
    S
)

Signed-off-by: Srishti Sharma <srishtishar@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>