Fix inconsistency between mbed crc and psoc6 crc implementations.

[dustin-crossman]

Summary of changes

There is an incongruity between what MBeds CRC spec expects and what PSoC6 hardware actually performs when it comes to the final XOR and remainder reversal: MBed expects the final remainder to be reversed then XORed while PSoC6s CRC, however, performs the final XOR then reverses the resulting value.
This fixes this by reversing the final XOR value before feeding it to the PSoC6 hardware. This works because

Rev(A) XOR B == Rev( A XOR Rev(B) )

Impact of changes

Migration actions required

Documentation

None

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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

CY8CKIT_062_WIFI_BT-GCC_ARM_GT.txt
CY8CPROTO_062_4343W-GCC_ARM_GT.txt

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Reviewers

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[ciarmcom]

@dustin-crossman, thank you for your changes.
@maclobdell @ARMmbed/mbed-os-maintainers please review.

[kjbracey]

Personally, I wouldn't bother with the assert - this is internal, and you've already cleared the HAL_CRC_IS_SUPPORTED check, and there are a squillion uint32_ts around here. 32-bit or less is kind of assumed.

Actually though, having this after HAL_CRC_IS_SUPPORTED means the compiler should hopefully skip putting in the assert anyway. So maybe I shouldn't be worrying about code size.

[kjbracey]

Has this newly shown up due to the extra Greentea tests? Good. I did recently add some to try to catch this possible error - it was clear the reversal of XOR and init values wasn't being exercised fully.

[dustin-crossman]

@kjbracey-arm Yep! The crc test cases you added was exactly what was failing for us.

[kjbracey]

CI started

[mbed-ci]

Test run: SUCCESS

Summary: 11 of 11 test jobs passed
Build number : 1
Build artifacts

[mergify]

This PR does not contain release version label after merging.

[0xc0170]

I've fixed the version: Set to 6.0.0-alpha-2