design: replace tx_data shift reg with fifo cache.

Implement TX Data Cache (FIFO like). TX Data are
stored at the time of regular sample point and read at
the time of secondary sample point.

Signed-off-by: Ille, Ondrej, Ing <illeondr@fel.cvut.cz>
4 jobs for 230-can-fd-tx-bit-error-detection-optimization in 12 minutes (queued for 4 seconds)
Status Job ID Name Coverage
  Build
passed #27612
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build_driver

00:00:16

passed #27611
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build_ip_and_tests

00:01:09

passed #27613
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build_linux_driver

00:00:17

 
  Test
passed #27614
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test_ip_fast

00:10:16

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