boot hangs when booting from SD card

When using your current 5.6 DT (with removed rockchip_suspend node, cause we currently don't patch the needed drivers into our kernel) on top of a 5.4 mainline kernel the booting from SD card with removed eMMC module hangs with:

[    4.192716] mmc_host mmc1: Timeout sending command (cmd 0x202000 arg 0x0 status 0x80202000)
[    4.229615] mmc1: error -110 whilst initialising SD card
[    4.731066] dwmmc_rockchip fe320000.dwmmc: Busy; trying anyway
[    5.231588] mmc_host mmc1: Timeout sending command (cmd 0x202000 arg 0x0 status 0x80202000)
[    5.246311] mmc_host mmc1: Bus speed (slot 0) = 300000Hz (slot req 300000Hz, actual 300000HZ div = 0)
[    5.777368] dwmmc_rockchip fe320000.dwmmc: Busy; trying anyway
[    6.277923] mmc_host mmc1: Timeout sending command (cmd 0x202000 arg 0x0 status 0x80202000)
[    6.292882] mmc_host mmc1: Bus speed (slot 0) = 200000Hz (slot req 200000Hz, actual 200000HZ div = 0)
[    6.830750] dwmmc_rockchip fe320000.dwmmc: Busy; trying anyway
[    7.331299] mmc_host mmc1: Timeout sending command (cmd 0x202000 arg 0x0 status 0x80202000)
[    7.346154] mmc_host mmc1: Bus speed (slot 0) = 100000Hz (slot req 100000Hz, actual 100000HZ div = 0)

by bringing back vqmmc-supply = <&vcc_sdio>; in the sdmmc node which was removed with 48a23282 the board comes up again. I use a SanDisk 32GB A1 card. Was vqmmc-supply removed on purpose due to a change between 5.4 and 5.6?