AD35XXR: Add/update support to the AD3541R, AD3542R, AD3551R, Ad3552R (…

…#1472)

* AD35XX: update documentation

Adapted documentation for the axi_ad35xxr to include
the four DACs: AD3541R, AD3542R, AD3551R, and AD3552R.

Adapted AD355xR_EVB to include information about the
AD3551R and AD3552R.

Inserted information about the QSPI_SEL pin.

Inserted MULTI_IO_MODE reg to the remap of
the ad3552r.

Signed-off-by: <[email protected]>

* AD35XX: Update library

It is supporting single SPI (Classic), dual SPI, and Quad SPI
(according to the eval limitations) for the DACs AD3541R,
AD3542R, AD3551R, AD3552R.

Changed the regmap, the reg DAC_CUSTOM_CTRL needs to assert
the MULTI_IO_MODE field to choose the SPI mode on the AXI
controller.

Removed axi_ad3552r library because it was substituted by
axi_ad35xxr.

Signed-off-by: Carlos Souza <[email protected]>

* AD35XX: Update project

It is supporting single SPI (Classic), dual SPI, and Quad SPI
(according to the eval limitations) for the DACs AD3541R,
AD3542R, AD3551R, AD3552R.

Removed evaluation board project ad3552r_evb because
it was substituted by ad35xxr_evb.

Signed-off-by: Carlos Souza <[email protected]>

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Signed-off-by: <[email protected]>
Signed-off-by: Carlos Souza <[email protected]>