riscv: undo portability problems introduced with 9p mount device

Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>

sys/src/9/amd64/core.json

@@ -103,6 +103,7 @@
 			"archamd64.c",
 			"asm.c",
 			"backtrace.c",
+			"../port/dev9p.c",
 			"../port/devbridge.c",
 		        "coreboot.c",
 			"ctype.c",

sys/src/9/amd64/devarch.c

@@ -546,6 +546,8 @@ void
 archinit(void)
 {
 	addarchfile("cputype", 0444, cputyperead, nil);
+	addarchfile("numcores", 0444, numcoresread, nil);
+	addarchfile("mtags", 0444, mtagsread, nil);
 }
 
 void

sys/src/9/port/devcons.c

@@ -382,7 +382,6 @@ enum{
 	Quser,
 	Qzero,
 	Qsyscall,
-	Qmtags,
 	Qdebug,
 };
 
@@ -417,7 +416,6 @@ static Dirtab consdir[]={
 	"user",		{Quser},	0,		0666,
 	"zero",		{Qzero},	0,		0444,
 	"syscall",	{Qsyscall},	0,		0666,
-	"mtags",	{Qmtags},	0,		0666,
 	"debug",	{Qdebug},	0,		0666,
 };
 
@@ -667,9 +665,6 @@ consread(Chan *c, void *buf, int32_t n, int64_t off)
 	case Qdrivers:
 		return devtabread(c, buf, n, off);
 
-	case Qmtags:
-		return mtagsread(c, buf, n, off);
-
 	case Qzero:
 		memset(buf, 0, n);
 		return n;

sys/src/9/port/port.json

@@ -40,7 +40,6 @@
 			"../port/devtab.c",
 			"../port/devtrace.c",
 			"../port/devuart.c",
-			"../port/dev9p.c",
 			"../port/devwd.c",
 			"../port/devws.c",
 			"../port/edf.c",