fix am335x_dmtimer.c

[oh]

Summary

ti/am335x: Fix the device_set_descf() call in am335x_dmtimer_probe()

Fixes: 459dc61c8b05 ("arm: Convert drivers to use device_set_desc(f)()")

(This is more or less the same as 3ce9b2ee9404381a002316df670939a3bd3c994f but for the am335x_dmtimer.c)

[markj]

Apologies for missing this. It looks like this file isn't compiled into any existing kernel config. Is that expected?

[imp]

I think this is in the TI kernel that's kinda on the way out unless it gets fixed... and oskar has been fixing it up...