allow to use z_move, z_loan etc with pointers

[milyin]

• allowed to use macros "z_move", "z_loan", etc both with value and pointer. This is necessary if user want to use e.g. z_loan macro with const z_owned_xxx_t* p value:

void foo(const z_owned_xxx_t* v) {
   z_xxx_read(z_loan(v)); // z_loan accepts pointer, no need to write "z_loan(*v)"
}