[ARM] Fix ARM branch relocation range

Branches in the ARM architecture are restricted to a range of +/- 32MB.
However, the code in .../arch/arm/kernel/module.c::apply_relocate() was
checking offset against a range of +/- 64MB.

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