pw_unit_test/cmake: Fixes unit test source file compiler warnings

Corrects a typo in pw_add_test_generic which resulted in it
ignoring the PRIVATE_COMPILE_OPTIONS_DEPS_BEFORE argument.

Change-Id: Id0191d1e603be260633f3fd025c10ff27d9d2625
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/126905
Commit-Queue: Ewout van Bekkum <ewout@google.com>
Pigweed-Auto-Submit: Ewout van Bekkum <ewout@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
diff --git a/pw_unit_test/test.cmake b/pw_unit_test/test.cmake
index 3fce6de..08e268e 100644
--- a/pw_unit_test/test.cmake
+++ b/pw_unit_test/test.cmake
@@ -179,7 +179,7 @@
     PRIVATE_DEFINES
       ${arg_PRIVATE_DEFINES}
     PRIVATE_COMPILE_OPTIONS_DEPS_BEFORE
-      ${PRIVATE_COMPILE_OPTIONS_DEPS_BEFORE}
+      ${arg_PRIVATE_COMPILE_OPTIONS_DEPS_BEFORE}
     PRIVATE_COMPILE_OPTIONS
       ${arg_PRIVATE_COMPILE_OPTIONS}
     PRIVATE_LINK_OPTIONS