lib/stackdepot: rename hash table constants and variables

Give more meaningful names to hash table-related constants and variables:

1. Rename STACK_HASH_SCALE to STACK_HASH_TABLE_SCALE to point out that it
   is related to scaling the hash table.

2. Rename STACK_HASH_ORDER_MIN/MAX to STACK_BUCKET_NUMBER_ORDER_MIN/MAX
   to point out that it is related to the number of hash table buckets.

3. Rename stack_hash_order to stack_bucket_number_order for the same
   reason as #2.

No functional changes.

Link: https://lkml.kernel.org/r/f166dd6f3cb2378aea78600714393dd568c33ee9.1676063693.git.andreyknvl@google.com


Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>