drivers/spi/spi_flash: explicitly handle STMicro deep power state

In order to provide more consistent probing in future refactorings, pull out
the release from deep sleep path in STMicro's SPI flash probing function.
Call that function explicitly when RDID doesn't return anything at all.
The old STMicro parts, even if supporting RDID, won't decode that
instruction while in a deep power down state. Instead of re-issuing RDID after
the successful wake assume the id fixup is valid.

Change-Id: I46c47abcfb1376c1c3ce772f6f232857b8c54202
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38167
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/include/spi-generic.h

@@ -37,7 +37,6 @@
 #define VENDOR_ID_SPANSION			0x01
 #define VENDOR_ID_SST				0xbf
 #define VENDOR_ID_STMICRO			0x20
-#define VENDOR_ID_STMICRO_FF			0xff
 #define VENDOR_ID_WINBOND			0xef
 
 /* Controller-specific definitions: */