memory: atmel-sdramc: remove the driver

memory: atmel-sdramc: remove the driver

Driver does only clock request + enable for DDR clocks. DDR clocks are
enabled by bootloader and need to stay that way in Linux. To avoid having
these clocks disabled by clock subsystem in case there are no Linux
consumers for them the clocks were marked as critical in clock drivers
(in commit 68b3b6f1773d ("clk: at91: mark ddr clocks as critical")).
With this, there is no need to have a separate driver that only does
clock request + enable.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230516072405.2696225-1-claudiu.beznea@microchip.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>