support/config-fragments: remove bogus BR2_JLEVEL option

There is no reason to have a BR2_JLEVEL option in such toolchain
defconfigs.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/config-fragments/autobuild/br-xtensa-full-internal.config

@@ -1,4 +1,3 @@
 BR2_xtensa=y
-BR2_JLEVEL=8
 BR2_TOOLCHAIN_BUILDROOT_LOCALE=y
 BR2_TOOLCHAIN_BUILDROOT_CXX=y