arm64: dts: hisilicon: hi6220-hikey: drop unit addresses from fixed regulators

arm64: dts: hisilicon: hi6220-hikey: drop unit addresses from fixed regulators

Fixed regulators are not part of any MMIO bus, so they should not have
unit addresses.  This fixes dtc W=1 warnings:

  hi6220-hikey.dts:85.26-92.4: Warning (unit_address_vs_reg): /regulator@0: node has a unit name, but no reg or ranges property
  hi6220-hikey.dts:94.27-102.4: Warning (unit_address_vs_reg): /regulator@1: node has a unit name, but no reg or ranges property
  hi6220-hikey.dts:104.26-113.4: Warning (unit_address_vs_reg): /regulator@2: node has a unit name, but no reg or ranges property

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>