checkpatch: prefer ether_addr_copy to memcpy(foo, bar, ETH_ALEN)

ether_addr_copy was added for kernel version 3.14.  It's slightly
smaller/faster for some arches.  Encourage its use.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -4087,6 +4087,16 @@ sub process {
 			}
 		}
 
+# Check for memcpy(foo, bar, ETH_ALEN) that could be ether_addr_copy(foo, bar)
+		if ($^V && $^V ge 5.10.0 &&
+		    $line =~ /^\+(?:.*?)\bmemcpy\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*ETH_ALEN\s*\)/s) {
+			if (WARN("PREFER_ETHER_ADDR_COPY",
+				 "Prefer ether_addr_copy() over memcpy() if the Ethernet addresses are __aligned(2)\n" . $herecurr) &&
+			    $fix) {
+				$fixed[$linenr - 1] =~ s/\bmemcpy\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*ETH_ALEN\s*\)/ether_addr_copy($2, $7)/;
+			}
+		}
+
 # typecasts on min/max could be min_t/max_t
 		if ($^V && $^V ge 5.10.0 &&
 		    defined $stat &&