CVE-2026-43380: hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read

In the Linux kernel, the following vulnerability has been resolved:

hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read

The q54sj108a2debugfsread function suffers from a stack buffer overflow due to incorrect arguments passed to bin2hex(). The function currently passes 'data' as the destination and 'datachar' as the source.

Because bin2hex() converts each input byte into two hex characters, a 32-byte block read results in 64 bytes of output. Since 'data' is only 34 bytes (I2CSMBUSBLOCKMAX + 2), this writes 30 bytes past the end of the buffer onto the stack.

Additionally, the arguments were swapped: it was reading from the zero-initialized 'datachar' and writing to 'data', resulting in all-zero output regardless of the actual I2C read.

Fix this by: 1. Expanding 'datachar' to 66 bytes to safely hold the hex output. 2. Correcting the bin2hex() argument order and using the actual read count. 3. Using a pointer to select the correct output buffer for the final simplereadfrombuffer call.