flash_ec: no stderr redirection in flashrom run
flash_ec: no stderr redirection in flashrom run

This patch removes stderr redirection in running flashrom
to flash-size, so that flash_ec log would contain more
information on error cases. It could be verbose even
for success case, but flash_ec script would take the last
output in number as SPI_SIZE.

BUG=none
BRANCH=none
TEST=manually ran flash_ec with Suzy-Q and Servo_Micro on reef.

- success case
$ ./util/flash_ec --chip=npcx_spi --image ${IMG} --verbose
INFO: EC build system didn't recognize . Assuming no baseboard.
INFO: Using ccd_cr50.
...
INFO: Running flashrom:
 sudo /usr/sbin/flashrom -p raiden_debug_spi:target=EC,
 serial=0580300D-91984377 --flash-size
flashrom v0.9.9  :  :  on Linux 5.2.17-1rodete3-amd64 (x86_64)
flashrom v0.9.9  :  :  on Linux 5.2.17-1rodete3-amd64 (x86_64)
 bus=0x01,address=0x43 | Cr50
INFO: Programming EC firmware image.
INFO: Running flashrom:
...

- failure case: servo_micro was not connected to the dut.
$ ./util/flash_ec --chip=npcx_spi --image ${IMG} --verbose
INFO: EC build system didn't recognize . Assuming no baseboard.
INFO: Using servo_v4_with_servo_micro.
...
INFO: Running flashrom:
 sudo /usr/sbin/flashrom -p raiden_debug_spi:serial=SNCQ03109
--flash-size
flashrom v0.9.9  :  :  on Linux 5.2.17-1rodete3-amd64 (x86_64)
flashrom v0.9.9  :  :  on Linux 5.2.17-1rodete3-amd64 (x86_64)
 bus=0x01,address=0x17 | Servo Micro
No EEPROM/flash device found.
ERROR: Failed to determine chip size!
INFO: Restoring servo settings...
dut-control --port=9999 cold_reset:off
dut-control --port=9999 spi1_vref:off
dut-control --port=9999 spi1_buf_en:off
dut-control --port=9999 cold_reset:on
dut-control --port=9999 cold_reset:off

Change-Id: I642f62081e92bec68d01dcf4e2a4bb71a0131163
Signed-off-by: Namyoon Woo <e8732cefb861f07768f47df788a8e8eb75efc09a@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2031644
Reviewed-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec