ARM: highbank: remove incorrect BSYM usage

BSYM macro is only needed for assembly files and its usage in c files is
wrong, so remove it. The linker will correctly set bit 0 for Thumb2
kernels.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Dave Martin <dave.martin@linaro.org>