CVE-2026-46001: hwmon: (pt5161l) Fix bugs in pt5161l_read_block_data()

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

hwmon: (pt5161l) Fix bugs in pt5161lreadblockdata()

Fix two bugs in pt5161lreadblockdata():

1. Buffer overrun: The local buffer rbuf is declared as u8 rbuf[24], but i2csmbusreadblockdata() can return up to I2CSMBUSBLOCKMAX (32) bytes. The i2c-core copies the data into the caller's buffer before the return value can be checked, so the post-read length validation does not prevent a stack overrun if a device returns more than 24 bytes. Resize the buffer to I2CSMBUSBLOCKMAX.

2. Unexpected positive return on length mismatch: When all three retries are exhausted because the device returns data with an unexpected length, i2csmbusreadblockdata() returns a positive byte count. The function returns this directly, and callers treat any non-negative return as success, processing stale or incomplete buffer contents. Return -EIO when retries are exhausted with a positive return value, preserving the negative error code on I2C failure.