[openwrt/openwrt] base-files: remove unneeded '$' signs in nand.sh

[LEDE Commits]

dangole pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/287bd78e6f8af68fc3095839c7b70842cf3ddb4c

commit 287bd78e6f8af68fc3095839c7b70842cf3ddb4c
Author: Daniel Golle <daniel at makrotopia.org>
AuthorDate: Wed Feb 24 11:40:50 2021 +0000

    base-files: remove unneeded '$' signs in nand.sh
    
    When using Shell arithmetric evaluation via $((..)) the variables in
    the expression do not need to be prefixed by the '$' sign.
    
    Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
 package/base-files/files/lib/upgrade/nand.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/package/base-files/files/lib/upgrade/nand.sh b/package/base-files/files/lib/upgrade/nand.sh
index 2b766480d7..faeb3d6fc1 100644
--- a/package/base-files/files/lib/upgrade/nand.sh
+++ b/package/base-files/files/lib/upgrade/nand.sh
@@ -118,7 +118,7 @@ nand_upgrade_prepare_ubi() {
 	local rootfs_length="$1"
 	local rootfs_type="$2"
 	local rootfs_data_max="$(fw_printenv -n rootfs_data_max 2>/dev/null)"
-	[ -n "$rootfs_data_max" ] && rootfs_data_max=$(($rootfs_data_max))
+	[ -n "$rootfs_data_max" ] && rootfs_data_max=$((rootfs_data_max))
 
 	local kernel_length="$3"
 	local has_env="${4:-0}"
@@ -195,7 +195,7 @@ nand_upgrade_prepare_ubi() {
 	if [ "$rootfs_type" != "ubifs" ]; then
 		local availeb=$(cat /sys/devices/virtual/ubi/$ubidev/avail_eraseblocks)
 		local ebsize=$(cat /sys/devices/virtual/ubi/$ubidev/eraseblock_size)
-		local avail_size=$(( $availeb * $ebsize ))
+		local avail_size=$((availeb * ebsize))
 		local rootfs_data_size_param="-m"
 		if [ -n "$rootfs_data_max" ] &&
 		   [ "$rootfs_data_max" != "0" ] &&