Remove -D__ASSEMBLER__=1 when shelling out to the preprocessor

The compiler already knows that .S means assembler and should define
__ASSEMBLER__ for us. At least on the CQ, it seems this is not
necessary, and some builds are showing a warning about redefining
__ASSEMBLER__, which may be caused by this.

Change-Id: I390bfcb50cefef42df72cd61ead55159b1838771
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/60785
Reviewed-by: Bob Beck <bbe@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Commit-Queue: Bob Beck <bbe@google.com>

util/fipstools/delocate/delocate.go

diff --git a/util/fipstools/delocate/delocate.go b/util/fipstools/delocate/delocate.go
index c28be55..b801d6d 100644
--- a/util/fipstools/delocate/delocate.go
+++ b/util/fipstools/delocate/delocate.go
@@ -1637,9 +1637,6 @@
 		// preprocessor, but we don't want the compiler complaining that
 		// "argument unused during compilation".
 		cppCommand = append(cppCommand, "-Wno-unused-command-line-argument")
-		// We are preprocessing for assembly output and need to simulate that
-		// environment for arm_arch.h.
-		cppCommand = append(cppCommand, "-D__ASSEMBLER__=1")
 
 		for includePath := range includePaths {
 			cppCommand = append(cppCommand, "-I"+includePath)