f2fs: fix 446 coding style warnings in f2fs.h

1) Nine coding style warnings below have been resolved:
"Missing a blank line after declarations"

2) 435 coding style warnings below have been resolved:
"function definition argument 'x' should also have an identifier name"

3) Two coding style warnings below have been resolved:
"macros should not use a trailing semicolon"

Signed-off-by: DongOh Shin <doscode.kr@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>