Use -gcv8 instead of -g cv8.

yasm accepts both, but nasm reportedly only accepts the former.

Change-Id: Iddcd33daac3f9063b4ddd50d82503b1984391c08
Reviewed-on: https://boringssl-review.googlesource.com/25004
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

crypto/CMakeLists.txt

@@ -53,7 +53,7 @@ if(NOT OPENSSL_NO_ASM)
       set(PERLASM_STYLE win32n)
       set(PERLASM_FLAGS "-DOPENSSL_IA32_SSE2")
     endif()
-    set(CMAKE_ASM_NASM_FLAGS "-g cv8")
+    set(CMAKE_ASM_NASM_FLAGS "-gcv8")
 
     # On Windows, we use the NASM output, specifically built with Yasm.
     set(ASM_EXT asm)