mtd: clean up whitespace in linux/mtd/map.h

As the only comments I got for the "mtd: cfi: reduce stack size"
patch were about whitespace changes, it appears necessary to fix
up the rest of the file as well, which contains the exact same
mistakes.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>