script/sorttable: Fix some initialization problems

elf_mcount_loc and mcount_sort_thread definitions are not
initialized immediately within the function, which can cause
the judgment logic to use uninitialized values when the
initialization logic of subsequent code fails.

Link: https://lkml.kernel.org/r/[e-mail]
Link: https://lkml.kernel.org/r/[e-mail]

Fixes: 72b3942a173c ("scripts: ftrace - move the sort-processing in ftrace_init")
Tested-by: Nathan Chancellor <[e-mail]>
Reviewed-by: Nathan Chancellor <[e-mail]>
Signed-off-by: Yinan Liu <[e-mail]>
Signed-off-by: Steven Rostedt <[e-mail]>

scripts/sorttable.h

···
 	return 0;
 }
 #ifdef MCOUNT_SORT_ENABLED
+pthread_t mcount_sort_thread;
+
 struct elf_mcount_loc {
 	Elf_Ehdr *ehdr;
 	Elf_Shdr *init_data_sec;
···
 	unsigned int shnum;
 	unsigned int shstrndx;
 #ifdef MCOUNT_SORT_ENABLED
-	struct elf_mcount_loc mstruct;
+	struct elf_mcount_loc mstruct = {0};
 	uint_t _start_mcount_loc = 0;
 	uint_t _stop_mcount_loc = 0;
-	pthread_t mcount_sort_thread;
 #endif
 #if defined(SORTTABLE_64) && defined(UNWINDER_ORC_ENABLED)
 	unsigned int orc_ip_size = 0;