jump_label: remove workaround for old compilers in initializations

jump_label: remove workaround for old compilers in initializations

The extra braces for the initialization of the anonymous union members
were added in commit cd8d860dcce9 ("jump_label: Fix anonymous union
initialization") to compensate for limitations in gcc < 4.6.

Versions of gcc this old are not supported anymore,
so drop the workaround.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260313-jump_label-cleanup-v2-2-35d3c0bde549@linutronix.de