libbpf-tools: memleak tools fails to build on ppc64

The libpf tool memleak fails to build on powerpc 64 with the following error:
```
BPF memleak.bpf.o
memleak.bpf.c:377:23: error: no member named 'bytes_alloc' in 'struct trace_event_raw_percpu_alloc_percpu'
gen_alloc_enter(ctx->bytes_alloc);
~~~ ^
1 error generated.
make: *** [Makefile:198: /builddir/build/BUILD/bcc-0.27.0/libbpf-tools/.output/memleak.bpf.o] Error 1
```
The field `bytes_alloc` is indeed missing from `trace_event_raw_percpu_alloc_percpu` in powerpc vmlinux.h.
I don't see what makes ppc64 different than other arches here.

bcc version: 0.27.0
Kernel version: 6.2.8-200.fc37.ppc64le

Start with libbpf-tools/memleak.bpf.c around line 377 and inspect the generated powerpc vmlinux.h definition of trace_event_raw_percpu_alloc_percpu. Check the libbpf-tools build rule referenced at Makefile line 198 and compare the relevant event fields across architectures. Done means memleak.bpf.o builds successfully on ppc64 without the missing bytes_alloc error.

Written by the indexing model from the issue text.