can: mcp25xxfd: optimize TEF read avoiding unnecessary SPI transfers

We have already enough information to know how many tx-messages have
been terminated so that we do not have to query TEF every time if
there is anything pending but we can read the tefs blindly.

This avoids 1 SPI transfer per TEF read.

Change-Id: Ib1a9e4ad2369b88ec4a277c010fc2e729c83dab6
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Git-commit: d86b4846
Git-repo: https://github.com/msperl/linux-rpi/releases/tag/mcp25xxfd-V8.2


Signed-off-by: Ke Du <quic_kedu@quicinc.com>