perf intel-pt: Fix exclude_guest setting

perf intel-pt: Fix exclude_guest setting

In the past, the exclude_guest setting has had no effect on Intel PT
tracing, but that may not be the case in the future.

Set the flag correctly based upon whether KVM is using Intel PT
"Host/Guest" mode, which is determined by the kvm_intel module
parameter pt_mode:

 pt_mode=0	System-wide mode : host and guest output to host buffer
 pt_mode=1	Host/Guest mode : host/guest output to host/guest
                buffers respectively

Fixes: 6e86bfdc4a60 ("perf intel-pt: Support decoding of guest kernel")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20240625104532.11990-3-adrian.hunter@intel.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>