spi: Use bus probing for SFDP

Only probe for the SFDP signature and split the actual SFDP parsing
into a chip preparation function.

Change-Id: I182d0a386bb2fd11951a1c9f2f965ce68ff57cf0
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/427
diff --git a/flashchips.c b/flashchips.c
index eb8e2fe..a573a25 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -27334,13 +27334,14 @@
 		/* want the default "This flash part has status UNTESTED..." */
 		/* text to be printed. */
 		.tested		= TEST_OK_PREW,
-		.probe		= probe_spi_sfdp,
+		.probe		= probe_buses,
 		.block_erasers	= {}, /* set by probing function */
 		.unlock		= spi_disable_blockprotect, /* is this safe? */
 		.write		= NULL, /* set by probing function */
 		.read		= spi_chip_read,
 		/* FIXME: some vendor extensions define this */
 		.voltage	= {0},
+		.prepare_access	= spi_prepare_sfdp,
 	},
 
 	{