[ARM] nommu: backtrace code must not reference a discarded section

The code in "1007:" is in the .fixup section, which in the mmuless
case is discarded.  Since this code is referenced from the .text
section, it causes an link error.  Move this code into the .text
section instead.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>