staging: speakup: use speakup_allocate as per required context

speakup_allocate used GFP_ATOMIC for allocations
even while during initialization due to it's use
in notifier call.

Pass GFP_ flags as well to speakup_allocate depending
on the context it is called in.

Signed-off-by: Pranay Kr. Srivastava <pranjas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>