net: qlcnic: validate unified ROM sections before loading

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

net: qlcnic: validate unified ROM sections before loading

The unified ROM parser reads directory, product, and data-descriptor fields
from the firmware file. Existing validation forms table and data ends with
unchecked additions and multiplications. Malformed values can wrap before
they are compared with the firmware size. The parser also dereferences
typed pointers at firmware-controlled offsets.

Valid descriptor extents alone are insufficient for the consumers. The
loader reads a fixed-size bootloader regardless of its declared size, the
version parser assumes a 17-byte tail, and a partial final firmware word is
read as a full u64. A truncated image can therefore make the driver read
beyond the firmware allocation during validation or loading.

Replace the pointer-returning parser with bounded range helpers. Validate
table entry sizes, descriptor indices, section ranges, the fixed
bootloader load length, and the version tail before exposing any section.
Read all file fields with unaligned little-endian accessors and assemble a
partial final word from only the bytes that remain. Apply the same range
checks to the legacy image before reading its fixed fields.