perf script python: Adjust objdump start/end per map pgoff parameter

perf script python: Adjust objdump start/end per map pgoff parameter

Extract map_pgoff parameter from the dictionary, and adjust start/end
range passed to objdump based on the value.

A zero start_addr is filtered to prevent output of dso address range
check failures. This script repeatedly sees a zero value passed
in for
      start_addr = cpu_data[str(cpu) + 'addr']

These zero values are not a new problem. The start_addr/stop_addr warning
clutters the instruction trace output, hence this change.

Signed-off-by: Steve Clevenger <scclevenger@os.amperecomputing.com>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Cc: suzuki.poulose@arm.com
Cc: james.clark@linaro.org
Cc: mike.leach@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org
Cc: ilkka@os.amperecomputing.com
Link: https://lore.kernel.org/r/21ccdd22e664bdeccb878672d4b2c0518873c1e5.1731027120.git.scclevenger@os.amperecomputing.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>