CVE-2026-23062: platform/x86: hp-bioscfg: Fix kernel panic in GET_INSTANCE_ID macro

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

platform/x86: hp-bioscfg: Fix kernel panic in GETINSTANCEID macro

The GETINSTANCEID macro that caused a kernel panic when accessing sysfs attributes:

1. Off-by-one error: The loop condition used '<=' instead of '<', causing access beyond array bounds. Since array indices are 0-based and go from 0 to instancescount-1, the loop should use '<'.

2. Missing NULL check: The code dereferenced attrnamekobj->name without checking if attrnamekobj was NULL, causing a null pointer dereference in minlengthshow() and other attribute show functions.

The panic occurred when fwupd tried to read BIOS configuration attributes:

Oops: general protection fault [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:minlengthshow+0xcf/0x1d0 [hpbioscfg]

Add a NULL check for attrnamekobj before dereferencing and corrects the loop boundary to match the pattern used elsewhere in the driver.