The noinstr attribute is to be specified before the return type in the
same way 'inline' is used.

Similar cases were recently fixed for x86 in commit 7f6fa101 ("x86:
Correct noinstr qualifiers"), but the generic entry code was based on the
the original version and did not carry the fix over.

Fixes: a5497bab ("entry: Provide generic interrupt entry/exit code")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200725091951.744848-3-mingo@kernel.org