drm/i915/bios: fix a memory leak in generate_lfp_data_ptrs

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

drm/i915/bios: fix a memory leak in generate_lfp_data_ptrs

When (size != 0 || ptrs->lvds_ entries != 3), the program tries to free() the ptrs. However, the ptrs is not created by calling kzmalloc(), but is obtained by pointer offset operation. This may lead to memory leaks or undefined behavior.

Fix this by replacing the arguments of kfree() with ptrs_block.

(cherry picked from commit 7674cd0b7d28b952151c3df26bbfa7e07eb2b4ec)