doc: fix :file: reference to include file
doc: fix :file: reference to include file

fix reference to  include/toolchain/gcc.h

Change-Id: I5999e17a5aed7c2f2e9cce40750815be30b6de53
Signed-off-by: David B. Kinder <c56c8b29908a5b2af1b63001268d73a0b7f972ba@intel.com>

tidyjiang8/zephyr-doc,tidyjiang8/zephyr-doc,tidyjiang8/zephyr-doc,tidyjiang8/zephyr-doc,tidyjiang8/zephyr-doc