libpayload: Take flash parameters from coreboot

A payload may want to run erase operations on SPI NOR flash without
re-probing the device to get its properties. This patch passes up
three properties of flash to achieve that:
- The size of the flash device
- The sector size, i.e., the granularity of erase
- The command used for erase
The patch sends the parameters through coreboot and then libpayload.
The patch also includes a minor refactoring of the flash erase code.
Parameters are sent up for just one flash device. If multiple SPI
flash devices are probed, the second one will "win" and its
parameters will be sent up to the payload.

TEST=Observed parameters to be passed up to depthcharge through
libpayload and be used to correctly initialize flash and do an erase.
TEST=Winbond and Gigadevices spi flash drivers compile with the changes;
others don't, for seemingly unrelated reasons.
BRANCH=none
BUG=chromium:446377

Change-Id: I92b7ff0ce66af8d096ec09a4c900829ef6c867e0
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 988c8c68bbfcdfa69d497ea5f806567bc80f8126
Original-Change-Id: Ie2b3a7f5b6e016d212f4f9bac3fabd80daf2ce72
Original-Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/239570
Original-Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://review.coreboot.org/9727
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/payloads/libpayload/include/sysinfo.h b/payloads/libpayload/include/sysinfo.h
index aa594c9..ec8a31c 100644
--- a/payloads/libpayload/include/sysinfo.h
+++ b/payloads/libpayload/include/sysinfo.h
@@ -118,6 +118,11 @@
 	void		*wifi_calibration;
 	uint64_t	ramoops_buffer;
 	uint32_t	ramoops_buffer_size;
+	struct spi_flash {
+		uint32_t size;
+		uint32_t sector_size;
+		uint32_t erase_cmd;
+	} spi_flash;
 };
 
 extern struct sysinfo_t lib_sysinfo;