docs: trace: Fix typo in ftrace.rst

There is a typo in the sentence "A kernel developer must be
conscience ...". The word conscience should be conscious.
This patch fixes it.

Signed-off-by: Lin Yu Chen <starpt.official@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230412183739.89894-1-starpt.official@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Author: Lin Yu Chen

Documentation/trace/ftrace.rst

@@ -3510,7 +3510,7 @@ directories, the rmdir will fail with EBUSY.
 Stack trace
 -----------
 Since the kernel has a fixed sized stack, it is important not to
-waste it in functions. A kernel developer must be conscience of
+waste it in functions. A kernel developer must be conscious of
 what they allocate on the stack. If they add too much, the system
 can be in danger of a stack overflow, and corruption will occur,
 usually leading to a system panic.