cmake: kobject: Fixed kobject text area overflow for optimization 0

We need to allocate extra memory region for the hash function
that the gperf generates. The linker will need to maintain
the same location counter between multiple linker stages. Reserving
memory will help in maintaing correct location counters between
multiple stages. The required memory varies with optimization level.
In order to keep the size of the compiled object consistent,
the kobject_hash.c is always compiled with -Os.

fixes #5226

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>