Enable MMC/I2C/GPIO/PMIC/REGULATOR/PCA953X DM drivers
for mx6sxsabreauto board. Drop non-DM code.

Note:
The i.MX DM drivers has such dependency.
  MXC GPIO -> MXC I2C -> PFUZE/REGULATOR
  MXC GPIO -> PCA953X
  MXC GPIO -> FSL_USDHC

So the drivers needs to be enabled all to avoid
compiling error.

The uboot dm tree log:
=> dm tree
 Class       Probed   Name
 ----------------------------------------
  root        [ + ]    root_driver
  thermal     [   ]    |-- imx_thermal
  simple_bus  [ + ]    |-- soc
  simple_bus  [ + ]    |   |-- aips-bus@02000000
  simple_bus  [   ]    |   |   |-- spba-bus@02000000
  gpio        [ + ]    |   |   |-- gpio@0209c000
  gpio        [ + ]    |   |   |-- gpio@020a0000
  gpio        [ + ]    |   |   |-- gpio@020a4000
  gpio        [ + ]    |   |   |-- gpio@020a8000
  gpio        [ + ]    |   |   |-- gpio@020ac000
  gpio        [ + ]    |   |   |-- gpio@020b0000
  gpio        [ + ]    |   |   |-- gpio@020b4000
  simple_bus  [   ]    |   |   |-- anatop@020c8000
  simple_bus  [   ]    |   |   |-- snvs@020cc000
  pinctrl     [ + ]    |   |   `-- iomuxc@020e0000
  pinconfig   [ + ]    |   |       `-- imx6x-sabreauto
  pinconfig   [ + ]    |   |           |-- i2c2grp-1
  pinconfig   [ + ]    |   |           |-- i2c3grp-2
  pinconfig   [   ]    |   |           |-- uart1grp
  pinconfig   [ + ]    |   |           |-- usdhc3grp
  pinconfig   [   ]    |   |           |-- usdhc3grp-100mhz
  pinconfig   [   ]    |   |           |-- usdhc3grp-200mhz
  pinconfig   [ + ]    |   |           |-- usdhc4grp
  pinconfig   [ + ]    |   |           `-- vccsd3grp
  simple_bus  [ + ]    |   |-- aips-bus@02100000
  mmc         [ + ]    |   |   |-- usdhc@02198000
  mmc         [ + ]    |   |   |-- usdhc@0219c000
  i2c         [ + ]    |   |   |-- i2c@021a4000
  i2c_generic [ + ]    |   |   |   |-- generic_8
  i2c_generic [ + ]    |   |   |   `-- generic_4e
  i2c         [ + ]    |   |   `-- i2c@021a8000
  gpio        [ + ]    |   |       |-- gpio@30
  gpio        [ + ]    |   |       `-- gpio@32
  simple_bus  [   ]    |   `-- aips-bus@02200000
  simple_bus  [   ]    |       `-- spba-bus@02200000
  simple_bus  [ + ]    `-- regulators
  regulator   [ + ]        `-- regulator@0

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>