use matched sdfree() for sdmalloc(), and free() for malloc().

Reference: /n/sources/patch/sdscsi-sdfree
Date: Fri Jul  4 06:15:06 CES 2014
Signed-off-by: lunaria21@gmail.com

--- /sys/src/9/port/sdscsi.c	Fri Jul  4 06:14:46 2014
+++ /sys/src/9/port/sdscsi.c	Fri Jul  4 06:14:45 2014
@@ -57,7 +57,7 @@
 		return 0;
 	}
 	memmove(unit->inquiry, inquiry, r->dlen);
-	free(inquiry);
+	sdfree(inquiry);
 
 	SET(status);
 	for(i = 0; i < 3; i++){
@@ -244,7 +244,7 @@
 		}
 		break;
 	}
-	free(p);
+	sdfree(p);
 	free(r);
 
 	if(ok)
@@ -298,7 +298,7 @@
 		 */
 		break;
 	}
-	sdfree(r);
+	free(r);
 
 	return status;
 }