[POWERPC] Rename prom_n_size_cells to of_n_size_cells

This is more consistent and gets us closer to the Sparc code.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/char/tpm/tpm_atmel.h b/drivers/char/tpm/tpm_atmel.h
index 3501c03..3c85200 100644
--- a/drivers/char/tpm/tpm_atmel.h
+++ b/drivers/char/tpm/tpm_atmel.h
@@ -54,7 +54,7 @@
 
 	reg = get_property(dn, "reg", &reglen);
 	naddrc = of_n_addr_cells(dn);
-	nsizec = prom_n_size_cells(dn);
+	nsizec = of_n_size_cells(dn);
 
 	of_node_put(dn);