spi: Use bus probing for ST95 RDID

As the SPI instruction used for probing conflicts with AT45DB chips,
let it only run at priority `1', when no flash chip was detected.

Change-Id: I61db0d6fa7be81d120bc84213c358498019dc52d
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/420
diff --git a/spi.c b/spi.c
index da66a68..d674a6d 100644
--- a/spi.c
+++ b/spi.c
@@ -170,6 +170,8 @@
 	{ 0, ID_SPI_RES3,	probe_spi_res,		NULL },
 	{ 0, ID_SPI_RES2,	probe_spi_res,		NULL },
 	{ 0, ID_SPI_RES1,	probe_spi_res,		NULL },
+	{ 1, ID_SPI_ST95,	probe_spi_st95,		(void *)(uintptr_t)3 },
+	{ 1, ID_SPI_ST95,	probe_spi_st95,		(void *)(uintptr_t)2 },
 };
 
 static bool spi_probe_match(const struct flashchip *chip, const struct id_info_ext *found)