arm: allwinner: dts: a20: Sync A20 dts(i) files from Linux 5.1-rc2

arm: allwinner: dts: a20: Sync A20 dts(i) files from Linux 5.1-rc2

Sync sun7i-a20 dts(i) files from Linux 5.1-rc2

Linux commit details about the sun7i-a20* sync:
"ARM: dts: sun7i: bananapi: Add GPIO banks regulators"
(sha1: 09c6572290f018d73ec2e812e28bada34d41815f)

Here are U-Boot specific dts changes.

- s/uart0_pins_a/uart0_pb_pins for
  sun7i-a20-ainol-aw1.dts
  sun7i-a20-m5.dts
  sun7i-a20-primo73.dts
  sun7i-a20-yones-toptech-bd1078.dts
  sunxi-itead-core-common.dtsi
- s/gmac_pins_mii_a/gmac_rgmii_pins for
  sun7i-a20-m5.dts
- drop i2c0, i2c1 pins from
  sunxi-itead-core-common.dtsi
- drop mmc0 pins from
  sun7i-a20-primo73.dts

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>