Make hw/sh4 configurable and add new CONFIG_* to the
default-configs/sh4*-softmmu.mak.

Signed-off-by: Ákos Kovács <akoskovacs@gmx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20190202072456.6468-13-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>