arch, board: squash lines for immediate return

Remove unneeded variables and assignments.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Minkyu Kang <mk7.kang@samsung.com>
Reviewed-by: Angelo Dureghello <angelo@sysam.it>
diff --git a/board/freescale/common/zm7300.c b/board/freescale/common/zm7300.c
index be5953a..a6c3e69 100644
--- a/board/freescale/common/zm7300.c
+++ b/board/freescale/common/zm7300.c
@@ -140,9 +140,7 @@
 /* Uses the DPM command RRP */
 u8 zm_read(uchar reg)
 {
-	u8 d;
-	d = dpm_rrp(reg);
-	return d;
+	return dpm_rrp(reg);
 }
 
 /* ZM_write --