Fix references to trace doc

The README.trace has been moved and converted to rst in commit dce26c7d56
("doc: move README.trace to HTML documentation"); fix all the remaining
references to this file.

Signed-off-by: Vincent Stehlé <vincent.stehle@arm.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

cmd/Kconfig

@@ -2832,8 +2832,8 @@ config CMD_TRACE
 	  Enables a command to control using of function tracing within
 	  U-Boot. This allows recording of call traces including timing
 	  information. The command can write data to memory for exporting
-	  for analysis (e.g. using bootchart). See doc/README.trace for full
-	  details.
+	  for analysis (e.g. using bootchart). See doc/develop/trace.rst
+	  for full details.
 
 config CMD_AVB
 	bool "avb - Android Verified Boot 2.0 operations"

doc/develop/tests_sandbox.rst

@@ -28,8 +28,8 @@ Some of the available tests are:
 
      - test/image/test-imagetools.sh - multi-file images
      - test/py/tests/test-fit.py     - FIT images
-  - tracing: test/trace/test-trace.sh tests the tracing system (see
-      README.trace)
+  - tracing: test/trace/test-trace.sh tests the tracing system
+    (see :doc:`trace`).
   - verified boot: test/py/tests/test_vboot.py
 
 If you change or enhance any U-Boot subsystem, you should write or expand a

lib/Kconfig

@@ -348,7 +348,7 @@ config TRACE
 	  Enables function tracing within U-Boot. This allows recording of call
 	  traces including timing information. The command can write data to
 	  memory for exporting for analysis (e.g. using bootchart).
-	  See doc/README.trace for full details.
+	  See doc/develop/trace.rst for full details.
 
 config TRACE_BUFFER_SIZE
 	hex "Size of trace buffer in U-Boot"