cmd: Change default tpm path to use correct defaults

[josephlr]

This makes sure gotpm does the right thing on systems that don't
support the RM.

Signed-off-by: Joe Richey joerichey@google.com

[jkl73]

LGTM, but why can't we have the default tpmpath logic here (instead of go-tpm)? I feel like that's a somewhat very specific use case in the cmd tool.

[josephlr]

LGTM, but why can't we have the default tpmpath logic here (instead of go-tpm)? I feel like that's a somewhat very specific use case in the cmd tool.

This is a good point. I updated the PR to not depend on google/go-tpm#256. Instead it just implements the logic in this package. This should make things easier, and it still solves the problem.

I also updated our dependencies and ran go mod tidy.