x86/alternative: Remove noinline from __ibt_endbr_seal[_end]() stubs

Due to the explicit 'noinline' GCC-7.3 is not able to optimize away the
argument setup of:

	apply_ibt_endbr(__ibt_endbr_seal, __ibt_enbr_seal_end);

even when X86_KERNEL_IBT=n and the function is an empty stub, which leads
to link errors due to missing __ibt_endbr_seal* symbols:

ld: arch/x86/kernel/alternative.o: in function `alternative_instructions':
alternative.c:(.init.text+0x15d): undefined reference to `__ibt_endbr_seal_end'
ld: alternative.c:(.init.text+0x164): undefined reference to `__ibt_endbr_seal'

Remove the explicit 'noinline' to help gcc optimize them away.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221011113803.956808-1-linmiaohe@huawei.com

Author: MiaoheLin

arch/x86/kernel/alternative.c

@@ -624,7 +624,7 @@ void __init_or_module noinline apply_ibt_endbr(s32 *start, s32 *end)
 
 #else
 
-void __init_or_module noinline apply_ibt_endbr(s32 *start, s32 *end) { }
+void __init_or_module apply_ibt_endbr(s32 *start, s32 *end) { }
 
 #endif /* CONFIG_X86_KERNEL_IBT */