Detect i.MX6q vs i.MX6dl variants, detect if hsic connected devices are populated

Rewrite the platform detection, use machine and soc_id from /sys/device/soc0 as first attempt, fallback to gfplatdetect and proc_cpuinfo if needed. Soc_id is an array in the platform struct that has to map to the read soc_id to select a platform.

Also added pinfunc headers to use macros for PAD-CTL.

HSIC detection: Query equipped resistors and enable related dt nodes

Added functions based on devmem2 code to use pure register based access.    
Set padmux and ctl to read out the gpios to detect if pull up or            
pulldowns are equipped.                                                     
Add fragment generation based on the results.                               

usbh2 and usb3503 and usbh3 are only enabled when the related               
pullups/pulldowns are equipped on the related gpios.                        

The direct registor access is needed as gfxml2dto runs in the old and       
the new environment, FNGSystem as well as yocto. Also the driver for        
usb3503 has one of the gpios opened sometimes.                              
The direct access is a bit hacky but should always lead to the correct      
readout even if the driver already holds the gpio or the pins are not       
configured at all. 

BCS 746-000417