config: rename SECCOMP to USE_SECCOMP

It seems that we have some kind of a symbol name conflict which causes
CONFIG_SECCOMP to always be read as y.

Unfortunatelly, I could not figure out what is causing this, but simply
renaming SECCOMP to USE_SECCOMP seems to properly work and leaves the
symbol unset unless arch dependencies are satisfied.

This fixes qoriq and others that dont support seccomp from failing due
to procd-seccomp package being selected to get included but it cannot be
built for them:
ERROR: unable to select packages:
  procd-seccomp (no such package):
    required by: base-files-1637~52b6c92479[procd-seccomp]

Fixes: 4c65359af49b ("build: fix including busybox, procd and apk/opkg in imagebuilder")
Link: https://github.com/openwrt/openwrt/pull/17048
Signed-off-by: Robert Marko <robimarko@gmail.com>
(cherry picked from commit a48ec449ccab0069e84a72837bf06ba543e53aec)

config/Config-build.in

@@ -423,7 +423,7 @@ menu "Global build settings"
 
 	endchoice
 
-	config SECCOMP
+	config USE_SECCOMP
 		bool "Enable SECCOMP"
 		select KERNEL_SECCOMP
 		select PACKAGE_procd-seccomp

package/base-files/Makefile

@@ -42,7 +42,7 @@ define Package/base-files
   DEPENDS:= \
 	+netifd +libc +jsonfilter +SIGNED_PACKAGES:usign +SIGNED_PACKAGES:openwrt-keyring \
 	+NAND_SUPPORT:ubi-utils +fstools +fwtool \
-	+SELINUX:procd-selinux +!SELINUX:procd +SECCOMP:procd-seccomp \
+	+SELINUX:procd-selinux +!SELINUX:procd +USE_SECCOMP:procd-seccomp \
 	+SELINUX:busybox-selinux +!SELINUX:busybox
   TITLE:=Base filesystem for OpenWrt
   URL:=http://openwrt.org/

package/system/procd/Makefile

@@ -71,7 +71,7 @@ endef
 define Package/procd-seccomp
   SECTION:=base
   CATEGORY:=Base system
-  DEPENDS:=@SECCOMP +libubox +libblobmsg-json
+  DEPENDS:=@USE_SECCOMP +libubox +libblobmsg-json
   TITLE:=OpenWrt process seccomp helper + utrace
 endef