wcn36xx: Return result of set_power_params in suspend

wcn36xx_smd_set_power_params() can return an error. For the purposes of
entering into suspend we need the suspend() function to trap and report
errors up the stack.

First step in this process is reporting the existing result code for
wcn36xx_smd_set_power_params().

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Benjamin Li <benl@squareup.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210605011140.2004643-2-bryan.odonoghue@linaro.org