spi: spi-uclass: Add new spi_get_bus_and_cs() implementation

spi: spi-uclass: Add new spi_get_bus_and_cs() implementation

Move legacy spi_get_bus_and_cs() code to _spi_get_bus_and_cs().

Add new spi_get_bus_and_cs() implementation which rely on DT
for speed and mode and don't need any drv_name nor dev_name
parameters. This will prepare the ground for next patch.

Update all callers to use _spi_get_bus_and_cs() to keep the
same behavior.

Signed-off-by: Patrice Chotard <[email protected]>
Cc: Marek Behun <[email protected]>
Cc: Jagan Teki <[email protected]>
Cc: Vignesh R <[email protected]>
Cc: Joe Hershberger <[email protected]>
Cc: Ramon Fried <[email protected]>
Cc: Lukasz Majewski <[email protected]>
Cc: Marek Vasut <[email protected]>
Cc: Wolfgang Denk <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: "Pali Rohár" <[email protected]>
Cc: Konstantin Porotchkin <[email protected]>
Cc: Igal Liberman <[email protected]>
Cc: Bin Meng <[email protected]>
Cc: Pratyush Yadav <[email protected]>
Cc: Sean Anderson <[email protected]>
Cc: Anji J <[email protected]>
Cc: Biwen Li <[email protected]>
Cc: Priyanka Jain <[email protected]>
Cc: Chaitanya Sakinam <[email protected]>