tools/mm: fix build warnings with musl-libc

tools/mm: fix build warnings with musl-libc

musl-libc warns about the following:

/home/florian/dev/buildroot/output/arm64/rpi4-b/host/aarch64-buildroot-linux-musl/sysroot/usr/include/sys/errno.h:1:2: attention: #warning redirecting incorrect #include <sys/errno.h> to <errno.h> [-Wcpp]
    1 | #warning redirecting incorrect #include <sys/errno.h> to <errno.h>
      |  ^~~~~~~
/home/florian/dev/buildroot/output/arm64/rpi4-b/host/aarch64-buildroot-linux-musl/sysroot/usr/include/sys/fcntl.h:1:2: attention: #warning redirecting incorrect #include <sys/fcntl.h> to <fcntl.h> [-Wcpp]
    1 | #warning redirecting incorrect #include <sys/fcntl.h> to <fcntl.h>
      |  ^~~~~~~

include errno.h and fcntl.h directly.

Link: https://lkml.kernel.org/r/20250210200518.1137295-1-florian.fainelli@broadcom.com
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>