power: reset: pwr-mlxbf: add missing include

Add missing include for devm_work_autocancel to fix build error:

drivers/power/reset/pwr-mlxbf.c: In function 'pwr_mlxbf_probe':
drivers/power/reset/pwr-mlxbf.c:67:15: error: implicit declaration of function 'devm_work_autocancel' [-Werror=implicit-function-declaration]
   67 |         err = devm_work_autocancel(dev, &priv->send_work, pwr_mlxbf_send_work);
      |               ^~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Fixes: a4c0094f ("power: reset: pwr-mlxbf: add BlueField SoC power control driver")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Asmaa Mnebhi <asmaa@nvidia.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>