Fix the vulnerabilty of #15462 issue

[fireknight-hJ]

Summary of changes

Set the stateRx variable to HCI_RX_STATE_IDLE when an invalid HCI packet type is detected, to prevent overflow in the hdrRx buffer.

Impact of changes

Migration actions required

Documentation

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Pull request type

[X] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[X] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

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[0xc0170]

@fireknight-hJ Thanks for the patch, cna you please remove the first commit (merge to your branch, instead do a rebase - there should be only one commit here in this pull request - on your branch).

[fireknight-hJ]

@fireknight-hJ Thanks for the patch, cna you please remove the first commit (merge to your branch, instead do a rebase - there should be only one commit here in this pull request - on your branch).

Done，Please let me know if there's anything else needed.