[SRU][F:linux-bluefield][PATCH v1 0/1] UBUNTU: SAUCE: pwr-mlxbf.c: Improve driver dependencies

[Asmaa Mnebhi]

Buglink: https://bugs.launchpad.net/bugs/1980750

SRU Justification:

[Impact]

Improve the driver dependency on the gpio driver. Move
that dependency to the probe as instructed by maintainers.
Flush if there is remaining work while the driver is removed.

[Fix]

* Instead of using SOFTDEP, return -EPROBE_DEFER if the gpio-mlxbf2.c driver is not loaded yet.
* Flush work when driver is removed.

[Test Case]

* Test case only valid on Board with BMC on it:
* Make sure driver is loaded and no errors in dmesg.
* issue a power reset from the BMC via IPMI.

[Regression Potential]

Any of the test cases above could be impacted due to these changes.