arch/um: partially revert the conversion to __section() macro

A couple of um files ended up not including the header file that defines
the __section() macro, and the simplest fix is to just revert the change
for those files.

Fixes: 33def849

 treewide: Convert macro and uses of __section(foo) to __section("foo")
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>