usb: dwc3: core: move dwc3_cache_hwparams before dwc3_alloc_event_buffers

commit 392142 moved event buffer allocation out of dwc3_core_init() but
event buffer allocation uses the cached copy of hwparams to determine
the number of event buffers and the caching is done in dwc3_core_init.
So moved dwc3_cache_hwparams function before dwc3_alloc_event_buffers so
that dwc3_alloc_event_buffers sees the correct number of event buffers.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>