edi: Split preparation/finalization out of edi_probe_kb9012()

This turns edi_probe_kb9012() into a pure probing function. To avoid
turning EDI off after probing, register edi_finish() only after full
preparation.

Change-Id: Icc342b8ab109d5621d8b65c79cecf71a44bea4bd
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/423
diff --git a/flashchips.c b/flashchips.c
index 37f85b6..02aaf88 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -4205,6 +4205,7 @@
 		.read		= edi_chip_read,
 		.voltage	= {2700, 3600},
 		.gran		= write_gran_128bytes,
+		.prepare_access	= edi_prepare,
 	},
 
 	{