[source] ARC: use -mcpu=XXX instead of obsolete -mXXX

[LEDE Commits]

blogic pushed a commit to source.git, branch master:
https://git.lede-project.org/0799de6d9ec29fba460d286bd54818bdb7034702

commit 0799de6d9ec29fba460d286bd54818bdb7034702
Author: Alexey Brodkin <Alexey.Brodkin at synopsys.com>
AuthorDate: Wed Feb 8 20:52:08 2017 +0300

    ARC: use -mcpu=XXX instead of obsolete -mXXX
    
    -mXXX option is deprecated already in arc-2016.03 toolchain
    and removed completely starting from arc-2016.09.
    
    Direct replacement is -mcpu=XXX which is already supported by
    arc-2016.03 used today in Lede.
    
    With that change we'll be ready for ARC toolchain update still
    keeping everything working with current tools.
    
    Signed-off-by: Alexey Brodkin <Alexey.Brodkin at synopsys.com>
    Cc: John Crispin <john at phrozen.org>
---
 include/target.mk | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/target.mk b/include/target.mk
index 3099448..5490d48 100644
--- a/include/target.mk
+++ b/include/target.mk
@@ -215,8 +215,8 @@ ifeq ($(DUMP),1)
   ifeq ($(ARCH),arc)
     CPU_TYPE ?= arc700
     CPU_CFLAGS += -matomic
-    CPU_CFLAGS_arc700 = -marc700
-    CPU_CFLAGS_archs = -marchs
+    CPU_CFLAGS_arc700 = -mcpu=arc700
+    CPU_CFLAGS_archs = -mcpu=archs
   endif
   DEFAULT_CFLAGS=$(strip $(CPU_CFLAGS) $(CPU_CFLAGS_$(CPU_TYPE)) $(CPU_CFLAGS_$(CPU_SUBTYPE)))