[dv] Shellcheck objdump script and check for RISCV_TOOLCHAIN variable
[dv] Shellcheck objdump script and check for RISCV_TOOLCHAIN variable

Signed-off-by: Marno van der Maas <140765e35f75d33bd28eb112371bcce78847cb8a@lowrisc.org>

lowRISC/ibex,lowRISC/ibex,lowRISC/ibex,lowRISC/ibex