Doesn't properly detect capacity >32GB

I have a card marked "SAMSUNG EVO 64" with the Micro SD XC logo. adafruit_sdcard detects its capacity as 57933824 512-byte blocks (0x3740000 blocks); other systems detect it as 125042688 512-byte blocks (0x7740000). Notice how the top bit is shaved off of the capacity number.

I didn't track it down fully, but it seems that the "v2 card" detection isn't complete; it leaves the card returning a "v1 csd", which is limited to 32GB.
```
card version check r= 1
card version v2
(58 #1) ocr= bytearray(b'@\xff\x80\x00')
(58 #1) ocr= bytearray(b'\xc0\xff\x80\x00')
(58 #2) ocr= bytearray(b'\xc0\xff\x80\x00')
csd version 1
csd 400e00325b590001dcff7f800a4040f1
```
I believe, but didn't verify, that e.g., my work in progess code to use SDIO on STM32F4 Feather is getting a csd version 2, but I didn't determine why/how yet.

This problem also exists in the WIP code for SD-over-SPI in the core, since it copied the "flow" of adafruit_sdcard.

Compare the v2 card and CSD handling in adafruit_sdcard with the WIP SD-over-SPI code in the core, starting from the card-version and CSD-version output shown here. Done means a 64GB SDXC card reports its full capacity instead of the truncated block count, with behavior covered by an appropriate regression check.

Written by the indexing model from the issue text.