sched: dynamic: Remove HAVE_PREEMPT_DYNAMIC_{CALL,KEY}

PREEMPT_DYNAMIC is now limited to the FULL and LAZY preemption models.
Switching model only changes the behaviour of dynamic_preempt_lazy(),
which uses a static key. There are no other static calls or static keys,
and so there's no need for HAVE_PREEMPT_DYNAMIC_CALL or
HAVE_PREEMPT_DYNAMIC_KEY.

The static key used by dynamic_preempt_lazy() is entirely local to
kernel/sched/core.c, and any architecture which selects
ARCH_HAS_PREEMPT_LAZY implements the necessary support. Remove
PREEMPT_DYNAMIC's dependencies on HAVE_PREEMPT_DYNAMIC_CALL and
HAVE_PREEMPT_DYNAMIC_KEY entirely, leaving the dependency on
ARCH_HAS_PREEMPT_LAZY.

For architectures which previously selected HAVE_PREEMPT_DYNAMIC_KEY,
PREEMPT_DYNAMIC will now be selected by default, matching x86. As the
runtime impact is limited to dynamic_preempt_lazy(), this shouldn't be
as concerning as previously (e.g. where calls to {cond,might}_resched()
stubs could introduce a measurable penalty).

As all of this can work without jump labels, JUMP_LABEL is not selected
explicitly. It is obviously preferable to have JUMP_LABEL enabled, but
this is not functionally necessary.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Tested-by: Mete Durlu <meted@linux.ibm.com>
Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Tested-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20260803191731.3244294-6-mark.rutland@arm.com