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: 4c65359af4 ("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>

include/toplevel.mk

@@ -78,7 +78,7 @@ _ignore = $(foreach p,$(IGNORE_PACKAGES),--ignore $(p))
 # Config that will invalidate the .targetinfo as they will affect
 # DEFAULT_PACKAGES.
 # Keep DYNAMIC_DEF_PKG_CONF in sync with target.mk to reflect the same configs
-DYNAMIC_DEF_PKG_CONF := CONFIG_USE_APK CONFIG_SELINUX CONFIG_SMALL_FLASH CONFIG_SECCOMP
+DYNAMIC_DEF_PKG_CONF := CONFIG_USE_APK CONFIG_SELINUX CONFIG_SMALL_FLASH CONFIG_USE_SECCOMP
 check-dynamic-def-pkg: FORCE
 	@+DEF_PKG_CONFS=""; \
 	if [ -f $(TOPDIR)/.config ]; then \