wct4xxp: t4_serial_setup() was called more often than necessary.

The driver iterates through all the spans on a given device during assignment,
checking for unassigned spans, but it was erroneously testing the span on which
assigned was called.

This just removes some unexpected behavior and provides a slight performance
increase on load and does not impact the functionality of the driver as far as
I'm aware.

Reported-by: Doug Bailey <dbailey@digium.com>
Signed-off-by: Shaun Ruffell <sruffell@digium.com>
(cherry picked from commit 9de213b1044c5e005d714b9cf00a367120d42392)
wcb4xxp: Allocate memory in hfc_decode_st_state() with GFP_ATOMIC.

hfc_decode_st_state() will be called from interrupt context when the debug flag
is set to 32. Therefore, must use GFP_ATOMIC when allocating memory.

Only affects the wcb4xxp driver when called with particular debug flags set.

Internal-Issue-ID: DAHLIN-314
Reported-by: Gerald Schnabel
Signed-off-by: Shaun Ruffell <sruffell@digium.com>