firmware: ti_sci: Fix polled mode during system suspend

Commit b9e8a7d9 ("firmware: ti_sci: Switch transport to polled
mode during system suspend") uses read_poll_timeout_atomic() macro
in ti_sci_do_xfer() to wait for completion when the system is
suspending. The break condition of the macro is set to "true" which
will cause it break immediately when evaluated, likely before the
TISCI xfer is completed, and always return 0. We want to poll here
until "done_state == true".

1) Change the break condition of read_poll_timeout_atomic() to
the bool variable "done_state".

2) The read_poll_timeout_atomic() returns 0 if the break condition
is met or -ETIMEDOUT if not. Since our break condition has changed
to "done_state", we also don't have to check for "!done_state" when
evaluating the return value.

Fixes: b9e8a7d9 ("firmware: ti_sci: Switch transport to polled mode during system suspend")

Signed-off-by: Georgi Vlaev <g-vlaev@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20221021185704.181316-1-g-vlaev@ti.com