flashrom: Make flashrom_path() use do_cmd()

This makes it so there is only one way in which we spawn a child
process.

BUG=none
BRANCH=none
TEST=ran "mosys eeprom map" on cyan which uses flashrom

Signed-off-by: David Hendricks <dhendrix@chromium.org>
Change-Id: If8e39485b4b80d374e4fbdd5951a0b671bc99a26
Reviewed-on: https://chromium-review.googlesource.com/319646
Reviewed-by: Shawn N <shawnn@chromium.org>
1 file changed