powerpc/eeh: Use a goto for recovery failures

The EEH recovery logic in eeh_handle_normal_event() has some pretty strange
flow control. If we remove all the actual recovery logic we're left with
the following skeleton:

	if (result != PCI_ERS_RESULT_DISCONNECT) {
		...
	}

	if (result != PCI_ERS_RESULT_DISCONNECT) {
		...
	}

	if (result == PCI_ERS_RESULT_NONE) {
		...
	}

	if (result == PCI_ERS_RESULT_CAN_RECOVER) {
		...
	}

	if (result == PCI_ERS_RESULT_CAN_RECOVER) {
		...
	}

	if (result == PCI_ERS_RESULT_NEED_RESET) {
		...
	}

	if ((result == PCI_ERS_RESULT_RECOVERED) ||
	    (result == PCI_ERS_RESULT_NONE)) {
		...
		goto out;
	}

	/*
	 * unsuccessful recovery / PCI_ERS_RESULT_DISCONECTED
	 * handling is here.
	 */
	...

	out:
	...

Most of the "if () { ... }" blocks above change "result" to
PCI_ERS_RESULT_DISCONNECTED if an error occurs in that recovery step. This
makes the control flow a bit confusing since it breaks the early-exit
pattern that is generally used in Linux. In any case we end up handling the
error in the final else block so why not just jump there directly? Doing so
also allows us to de-indent a bunch of code.

No functional changes.

[dja: rebase on top of linux-next + my preceeding refactor,
      move clearing the EEH_DEV_NO_HANDLER bit above the first goto so that
      it is always clear in the error handler code as it was before.]

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211015070628.1331635-2-dja@axtens.net