[spi_device] Fast Read Dual pre_dv
[spi_device] Fast Read Dual pre_dv

This commit adds Fast Read Dual ('h 3B) command to the pre_dv testcase.

Signed-off-by: Eunchan Kim <cb7bc7ceb22698f298c67faa994fd9ddf3cab298@opentitan.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan