s32 -> int
exfat: fix coding style for spacing

This patch fixes incorrect code spacing issues.
exfat: fix coding style for trailing statements

Fix trailing statements on same line errors.
exfat: fix comment style

Fixed C99 comment errors.
exfat: fix return parentheses error

Fixed unneeded parentheses in returns
exfat: fix braces coding style errors

Fix errors with coding style of braces.
exfat: fix assignment in if condition

This patch fixes assignments in if conditions.
report error when we run out of mountpoints
use proper format for printing size_t