asm-generic/hyperv: Add missing #include of nmi.h

The recent move of hv_do_rep_hypercall() to this file adds
a reference to touch_nmi_watchdog(). Its function definition
is included indirectly when compiled on x86, but not when
compiled on ARM64. So add the explicit #include.

No functional change.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1626058204-2106-1-git-send-email-mikelley@microsoft.comSigned-off-by: Wei Liu <wei.liu@kernel.org>

include/asm-generic/mshyperv.h

@@ -22,6 +22,7 @@
 #include <linux/atomic.h>
 #include <linux/bitops.h>
 #include <linux/cpumask.h>
+#include <linux/nmi.h>
 #include <asm/ptrace.h>
 #include <asm/hyperv-tlfs.h>