Run .prepare_access only once per flash context

There's only a single path now to create a flash context,  after
probing, and only when we want to access the flash chip next. So
there's no need to defer this preparation step anymore.

All preparation will be done in a single step. Hence we drop the
PREPARE_POST_PROBE and PREPARE_FULL steps and the enum.

Change-Id: I7cd4058dd0b52ad0e4be45e494c4533f689893d9
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/492
diff --git a/include/chipdrivers/opaque.h b/include/chipdrivers/opaque.h
index d6d3eba..8d9f660 100644
--- a/include/chipdrivers/opaque.h
+++ b/include/chipdrivers/opaque.h
@@ -25,8 +25,7 @@
 
 struct found_id *probe_opaque(const struct bus_probe *, const struct master_common *, const struct flashchip *);
 
-enum preparation_steps;
-int prepare_opaque(struct flashprog_flashctx *, enum preparation_steps);
+int prepare_opaque(struct flashprog_flashctx *);
 
 int read_opaque(struct flashprog_flashctx *, uint8_t *buf, unsigned int start, unsigned int len);
 int write_opaque(struct flashprog_flashctx *, const uint8_t *buf, unsigned int start, unsigned int len);