serial: pch_uart: trivail cleanup by removing the pch_uart_hal_request()

pch_uart_hal_request() has parameters which it never uses, also
it is very short, so merge it with its caller to make code cleaner.
No functional changes at all.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>