soc: qcom: pil: Avoid usage of variable length array

The function, pil_load_segs(), declares a bitmap (err_map)
as a Variable Length Array (VLA). VLAs are considered unfit
when it comes to security, performance, code quality, and so
on. Hence, allocate the memory dynamically for the same bitmap.

Change-Id: I4d226eb6ab9c27910db41bf87d881a30f32a6c74
Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>