fix dwmmc card detect

[br]

Summary

Card detect is broken on Altera Stratix10 so use a quirk

Test Plan

tested on Terasic DE10 Pro

[manu]

There is a property in the DTS for that :
https://cgit.freebsd.org/src/tree/sys/contrib/device-tree/src/arm64/altera/socfpga_stratix10_socdk.dts#n111
And we parse this in :
https://cgit.freebsd.org/src/tree/sys/dev/mmc/mmc_fdt_helpers.c#n124
And :
https://cgit.freebsd.org/src/tree/sys/dev/mmc/host/dwmmc.c#n530

So you just need to check this bit in dwmmc.c and don't need a new softc variable or anything in dwmmc_altera.c

[br]

Use broken-cd property

[manu]

sys/dev/mmc/host/dwmmc.c

484

I think that should be in () and no need for the '\'

[br]

Add ()