mlxbf-bootctl: Fix kernel panic due to buffer overflow

[Asmaa Mnebhi]

SRU Justification:

[Impact]

Running the following LTP (linux-test-project) script, causes
a kernel panic and a reboot of the DPU:
ltp/testcases/bin/read_all -d /sys -q -r 10

The above test reads all directory and files under /sys.
Reading the sysfs entry "large_icm" causes the kernel panic
due to a garbage value returned via i2c read. That garbage
value causes a buffer overflow in sprintf.

[Fix]

* Replace sprintf with snprintf. And also add missing lock and
increase the buffer size to PAGE_SIZE.

[Test Case]

* Run from linux:
ltp/testcases/bin/read_all -d /sys -q -r 10

[Regression Potential]

no known regression

[Bartlomiej Zolnierkiewicz (bzolnier)]

This bug is awaiting verification that the linux-bluefield/5.15.0-1020.22 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy' to 'verification-done-jammy'. If the problem still exists, change the tag 'verification-needed-jammy' to 'verification-failed-jammy'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!