tools/rtla: Fix clang warning about mount_point var size

In the Linux kernel, the following vulnerability has been resolved:

tools/rtla: Fix clang warning about mount_point var size

clang is reporting this warning:

$ make HOSTCC=clang CC=clang LLVM_IAS=1

[...]

clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions

-fstack-protector-strong -fasynchronous-unwind-tables

-fstack-clash-protection -Wall -Werror=format-security

-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS

$(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c

src/utils.c:548:66: warning: 'fscanf' may overflow; destination buffer in argument 3 has size 1024, but the corresponding specifier may require size 1025 [-Wfortify-source]

548 | while (fscanf(fp, "%*s %" STR(MAX_PATH) "s %99s %*s %*d %*d\n", mount_point, type) == 2) {

| ^

Increase mount_point variable size to MAX_PATH+1 to avoid the overflow.