ipw2x00: Remove a memory allocation failure log message

Axe a memory allocation failure log message. This message is useless and
incorrect (vmalloc is not used here for the memory allocation)

This has been like that since the very beginning of this driver in
commit 43f66a6c ("Add ipw2200 wireless driver.")

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200424154527.27309-1-christophe.jaillet@wanadoo.fr