dt-bindings: clock: Add AST2500/AST2600 HACE reset definition

Add HACE reset bit definition for AST2500/AST2600.

Signed-off-by: Neal Liu <neal_liu@aspeedtech.com>
Signed-off-by: Johnny Huang <johnny_huang@aspeedtech.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>