fix typo: prevent <= from rendering as an arrow in .adoc files

Escaped the `<=` symbol with a backslash (`\<=`) to ensure it renders correctly as "less than or equal to" instead of being interpreted as an arrow.

Signed-off-by: Peng Sun <peng.sun@arm.com>
Change-Id: I77e211ab45ee6c4136ee14205da4476ca367c47b