soc: intel_adsp: tools: cavstool: Fix fw_is_alive() and wait_fw_entered()

The fw_is_alive() depends on 'dsp' global variable which is assigned
from map_regs() return value. To make fw_is_alive() and
wait_fw_entered(), that calls fw_is_alive(), callable from another
module, the 'dsp' variable needs to be passed as an argument.

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>