Fix TinyHashMap to use generic hash_type instead of hash_t

TinyHashMap used hash_t(key) to generate hashcode. This
would not work for 64-bit pointers as hash_t is declared as
an uint32_t.

Replaced the hash_t(key) call to more generic android::hash_type(key).
This function is a template function declared in TypeHelpers.h and
has a version available for all data types including pointers.

Change-Id: I612cf18b49ca7c30b63f9d6938df68fed7d80d08
Signed-off-by: Ashok Bhat <ashok.bhat@arm.com>