ramips: use kiB instead of B for IMAGE_SIZE

This cosmetical patch is just meant to make comparing/checking
IMAGE_SIZE values easier.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/ramips/image/mt7620.mk

@@ -806,7 +806,7 @@ TARGET_DEVICES += sanlinking_d240
 
 define Device/sercomm_na930
   MTK_SOC := mt7620a
-  IMAGE_SIZE := 20m
+  IMAGE_SIZE := 20480k
   DEVICE_VENDOR := Sercomm
   DEVICE_MODEL := NA930
   DEVICE_PACKAGES := kmod-usb2 kmod-usb-ohci

target/linux/ramips/image/mt7621.mk

@@ -275,7 +275,7 @@ TARGET_DEVICES += iodata_wn-ax1167gr
 
 define Device/iodata_wn-gx300gr
   MTK_SOC := mt7621
-  IMAGE_SIZE := 7798784
+  IMAGE_SIZE := 7616k
   DEVICE_VENDOR := I-O DATA
   DEVICE_MODEL := WN-GX300GR
   DEVICE_PACKAGES := kmod-mt7603 wpad-basic

target/linux/ramips/image/rt288x.mk

@@ -83,7 +83,7 @@ TARGET_DEVICES += buffalo_wzr-agl300nh
 define Device/dlink_dap-1522-a1
   MTK_SOC := rt2880
   BLOCKSIZE := 64k
-  IMAGE_SIZE := 3801088
+  IMAGE_SIZE := 3712k
   DEVICE_VENDOR := D-Link
   DEVICE_MODEL := DAP-1522
   DEVICE_VARIANT := A1

target/linux/ramips/image/rt305x.mk

@@ -296,7 +296,7 @@ TARGET_DEVICES += belkin_f7c027
 define Device/buffalo_whr-g300n
   MTK_SOC := rt3052
   BLOCKSIZE := 64k
-  IMAGE_SIZE := 3801088
+  IMAGE_SIZE := 3712k
   DEVICE_VENDOR := Buffalo
   DEVICE_MODEL := WHR-G300N
   IMAGES += tftp.bin