[PPP]: remove redundant NULL pointer checks before kfree & vfree

kfree() and vfree() can both deal with NULL pointers. This patch removes 
redundant NULL pointer checks from the ppp code in drivers/net/

Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ppp_deflate.c

@@ -87,8 +87,7 @@ static void z_comp_free(void *arg)
 
 	if (state) {
 		zlib_deflateEnd(&state->strm);
-		if (state->strm.workspace)
-			vfree(state->strm.workspace);
+		vfree(state->strm.workspace);
 		kfree(state);
 	}
 }
@@ -308,8 +307,7 @@ static void z_decomp_free(void *arg)
 
 	if (state) {
 		zlib_inflateEnd(&state->strm);
-		if (state->strm.workspace)
-			kfree(state->strm.workspace);
+		kfree(state->strm.workspace);
 		kfree(state);
 	}
 }