mtd: denali: fix indents and other trivial things

- Fix indents
- Do not break a line unless it is longer than 80 columns
- Do not insert a whitespace before ';'
- Use whitespaces around operators
- Use braces for a "else" block where the "if" block uses ones.

Besides, eliminate all the warnings reported by checkpatch.pl:
- WARNING: quoted string split across lines
- WARNING: else is not generally useful after a break or return
- WARNING: Missing a blank line after declarations
- WARNING: Avoid line continuations in quoted strings
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>