binfmt_elf_fdpic: fix AUXV size calculation when ELF_HWCAP2 is defined

In the Linux kernel, the following vulnerability has been resolved: binfmt_elf_fdpic: fix AUXV size calculation when ELF_HWCAP2 is defined create_elf_fdpic_tables() does not correctly account the space for the AUX vector when an architecture has ELF_HWCAP2 defined. Prior to the commit 10e29251be0e ("binfmt_elf_fdpic: fix /proc/<pid>/auxv") it resulted in the last entry of the AUX vector being set to zero, but with that change it results in a kernel BUG. Fix that by adding one to the number of AUXV entries (nitems) when ELF_HWCAP2 is defined.