HID: bpf: fix hid_bpf_input_report() when hid-core is not ready

HID: bpf: fix hid_bpf_input_report() when hid-core is not ready

Reported by linux-next:
After merging the hid tree, today's linux-next build (x86_64 allmodconfig)
failed like this:

x86_64-linux-gnu-ld: vmlinux.o: in function `hid_bpf_input_report':
(.text+0x1c75181): undefined reference to `hid_input_report'

Caused by commit 9be50ac30a83 ("HID: bpf: allow to inject HID event
from BPF")

I just forgot to put the indirection in place.

Link: https://lore.kernel.org/linux-kernel/20240411105131.7830f966@canb.auug.org.au/
Fixes: 9be50ac30a83 ("HID: bpf: allow to inject HID event from BPF")
Link: https://lore.kernel.org/r/20240411-fix-hid-bpf-v1-1-4ae913031a8c@kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>