common/rc: drop unnecessary variable from _check_kernel_option()

The commit 0ca7b32 ("common/rc: Introduce _get_kernel_option()")
introduced the unnecessary local variable "value". Drop it.

Signed-off-by: Shin'ichiro Kawasaki <[email protected]>

Author: kawasaki

common/rc

@@ -215,8 +215,6 @@ _get_kernel_option() {
 
 # Check if kernel option $1 is defined.
 _check_kernel_option() {
-	local value
-
 	case "$(_get_kernel_option "$1")" in
 		y|m)
 			return 0;;