Fix build flags for ARMv7.

Taken from Debian:
https://salsa.debian.org/multimedia-team/x265/-/blob/master/debian/patches/0001-Fix-arm-flags.patch

From: Sebastian Ramacher <sramacher@debian.org>
Date: Wed, 26 Apr 2017 22:05:06 +0200
Subject: Fix arm* flags

---
 source/CMakeLists.txt | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -77,7 +77,7 @@ elseif(ARMMATCH GREATER "-1")
         add_definitions(-DX265_ARCH_ARM=1 -DX265_ARCH_ARM64=1 -DHAVE_ARMV6=0)
     else()
         message(STATUS "Detected ARM target processor")
-        add_definitions(-DX265_ARCH_ARM=1 -DX265_ARCH_ARM64=0 -DHAVE_ARMV6=1)
+        add_definitions(-DX265_ARCH_ARM=1)
     endif()
 else()
     message(STATUS "CMAKE_SYSTEM_PROCESSOR value `${CMAKE_SYSTEM_PROCESSOR}` is unknown")
@@ -252,10 +252,7 @@ if(GCC)
         else()
             find_package(Neon)
             if(CPU_HAS_NEON)
-                set(ARM_ARGS -mcpu=native -mfloat-abi=hard -mfpu=neon -marm -fPIC)
                 add_definitions(-DHAVE_NEON)
-            else()
-                set(ARM_ARGS -mcpu=native -mfloat-abi=hard -mfpu=vfp -marm)
             endif()
         endif()
     endif()
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