drivers/sdcard_spi: make 8-bit safe

[maribu]

Contribution description

• replace all ints and unsigneds with integers with fixed width
• replaced all signed integers of sizes with unsigned ones (sizes cannot be negative)
• made bitshifts 8-bit safe (e.g. 1 << 24 is valid on 32-bit, but undefined behavior on 8-bit, as a 16 bit wide int would be shifted by more than the type width)
• use void * / const void * for data buffers to ease use

Testing procedure

$ make BOARD=<RANDOM_BEEFY_AVR_BOARD_WITH_SD_CARD> -C examples/vfs_default
> vfs ls /sd0

2022-09-09 17:08:51,026 # main(): This is RIOT! (Version: 2022.10-devel-591-g494f5d-drivers/sdcard_spi)
2022-09-09 17:08:51,040 # mount points:
2022-09-09 17:08:51,046 # 	/sd0
2022-09-09 17:08:51,047 # 
2022-09-09 17:08:51,063 # data dir: /sd0
> vfs ls /sd0
2022-09-09 17:08:56,155 # vfs ls /sd0
2022-09-09 17:08:56,191 # FIXUP.DAT	7314 B
2022-09-09 17:08:56,210 # FIXUP4.DAT	5448 B
2022-09-09 17:08:56,234 # SYSTEM~1.MAP	4328313 B
2022-09-09 17:08:56,256 # START4.ELF	2228800 B
2022-09-09 17:08:56,275 # CONFIG~1	207723 B
2022-09-09 17:08:56,295 # VMLINU~1	19730944 B
2022-09-09 17:08:56,356 # START.ELF	2952960 B
2022-09-09 17:08:56,509 # ALPINE~1	25 B
2022-09-09 17:08:56,639 # OVERLAYS/
2022-09-09 17:08:56,769 # DTBS-R~1/
2022-09-09 17:08:56,908 # INITRA~1	4162721 B
2022-09-09 17:08:57,049 # BCM271~1.DTB	26894 B
2022-09-09 17:08:57,211 # BCM271~2.DTB	29011 B
2022-09-09 17:08:57,453 # BCM271~3.DTB	28392 B
2022-09-09 17:08:57,670 # CONFIG.TXT	378 B
2022-09-09 17:08:57,892 # BOOTCODE.BIN	52456 B
2022-09-09 17:08:58,114 # BCM271~4.DTB	26890 B
2022-09-09 17:08:58,336 # BCM271~5.DTB	49218 B
2022-09-09 17:08:58,578 # BCM283~1.DTB	20120 B
2022-09-09 17:08:58,899 # BCM283~2.DTB	20989 B
2022-09-09 17:08:59,200 # BCM283~3.DTB	20525 B
2022-09-09 17:08:59,502 # BCM283~4.DTB	19852 B
2022-09-09 17:08:59,800 # CMDLINE.TXT	162 B
2022-09-09 17:09:00,097 # USERCFG.TXT	92 B
2022-09-09 17:09:00,448 # CMDLINE.BAK	256 B
2022-09-09 17:09:00,916 # BCM271~6.DTB	49214 B
2022-09-09 17:09:01,364 # BCM271~7.DTB	49892 B
2022-09-09 17:09:01,633 # total 25 files

Issues/PRs references

Fixes issue reported in #18445 (comment)

[benpicco]

Looks good to me - please fix static checks

[maribu]

Thx :)