sdcard: replace VLA with static buffer, add card presence guard#205

bessman merged 2 commits into

fossasia:mainfossasia/pslab-firmware:mainfrom

dhruvmittal41:dhruv/fix/sdcard-static-buffer-and-presence-checkdhruvmittal41/pslab-firmware:dhruv/fix/sdcard-static-buffer-and-presence-checkCopy head branch name to clipboard