x86/mce: Add notifier_block forward declaration

Without linux/irq.h, there is no declaration of notifier_block, leading to
a build warning:

In file included from arch/x86/kernel/cpu/mcheck/threshold.c:10:
arch/x86/include/asm/mce.h:151:46: error: 'struct notifier_block' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]

It's sufficient to declare the struct tag here, which avoids pulling in
more header files.

Fixes: 447ae3166702 ("x86: Don't include linux/irq.h from asm/hardirq.h")
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Nicolai Stange <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

0 files changed, 0 insertions, 0 deletions