perf annotate: Return errors from disasm_line__parse_powerpc()

perf annotate: Return errors from disasm_line__parse_powerpc()

In disasm_line__parse_powerpc() , return code from function
disasm_line__parse() is ignored. This will result in bad results
if the disasm_line__parse() fails to disasm the line. Use
the return code to fix this.

Signed-off-by: Athira Rajeev <atrajeev@linux.ibm.com>
Tested-By: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Link: https://lore.kernel.org/r/20250304154114.62093-2-atrajeev@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>