riscv: dts: microchip: mpfs: remove bogus card-detect-delay

Recent versions of dt-schema warn about a previously undetected
undocumented property:
arch/riscv/boot/dts/microchip/mpfs-icicle-kit.dtb: mmc@20008000: Unevaluated properties are not allowed ('card-detect-delay' was unexpected)
        From schema: Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml

There are no GPIOs connected to MSSIO6B4 pin K3 so adding the common
cd-debounce-delay-ms property makes no sense. The Cadence IP has a
register that sets the card detect delay as "DP * tclk". On MPFS, this
clock frequency is not configurable (it must be 200 MHz) & the FPGA
comes out of reset with this register already set.

Fixes: bc47b221 ("riscv: dts: microchip: add the sundance polarberry")
Fixes: 0fa6107e ("RISC-V: Initial DTS for Microchip ICICLE board")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

arch/riscv/boot/dts/microchip/mpfs-icicle-kit.dts

@@ -100,7 +100,6 @@ &mmc {
 	disable-wp;
 	cap-sd-highspeed;
 	cap-mmc-highspeed;
-	card-detect-delay = <200>;
 	mmc-ddr-1_8v;
 	mmc-hs200-1_8v;
 	sd-uhs-sdr12;

arch/riscv/boot/dts/microchip/mpfs-polarberry.dts

@@ -70,7 +70,6 @@ &mmc {
 	disable-wp;
 	cap-sd-highspeed;
 	cap-mmc-highspeed;
-	card-detect-delay = <200>;
 	mmc-ddr-1_8v;
 	mmc-hs200-1_8v;
 	sd-uhs-sdr12;