The problem might be in your DT. I have a DT from TI that shows LCD7 working on BBB with touch. The main difference between that code and yours is how ehrpwm1 is set up in DT. Here is the TI file:
(Please visit the site to view this file)
The main difference I see that could cause the driver not to probe would be that you need to update your DT to look like this:
&epwmss1 { status = "okay"; ehrpwm1: ehrpwm@48302200 { status = "okay"; }; };