usb: dwc2: Rename GLPMCFG... definitions

Make field names of GLPMCFG register in definitions to be
the same with the databook.

Signed-off-by: Sevak Arakelyan <sevaka@synopsys.com>
Signed-off-by: Grigor Tovmasyan <tovmasya@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>