kernel/panic: mark init_taint_buf as __initdata and panic instead of warning in alloc...

kernel/panic: mark init_taint_buf as __initdata and panic instead of warning in alloc_taint_buf()

However there's a convention of assuming that __init-time allocations
cannot fail.  Because if a kmalloc() were to fail at this time, the kernel
is hopelessly messed up anyway.  So simply panic() if that kmalloc failed,
then make that 350-byte buffer __initdata.

Link: https://lkml.kernel.org/r/20260223035914.4033-1-rioo.tsukatsukii@gmail.com
Signed-off-by: Rio <rioo.tsukatsukii@gmail.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Wang Jinchao <wangjinchao600@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>