Remove duplicate includes across multiple files

This commit cleans up redundant header file includes throughout the codebase.
 The changes include:

 - Removing duplicate #include directives that were present in the same file
 - Consolidating includes that were split across multiple lines unnecessarily
 - Removing unused includes that were no longer needed
 - Fixing some formatting issues with includes

 The changes improve code organization and maintainability by:
 - Reducing unnecessary dependencies
 - Making include dependencies more explicit
 - Following consistent include patterns
 - Removing dead code

 No functional changes are made - this is purely a code cleanup commit.

Signed-off-by: Huang Qi <huangqi3@xiaomi.com>

libs/libc/pthread/pthread_spinlock.c

@@ -35,8 +35,6 @@
 #include <debug.h>
 #include <pthread.h>
 #include <sched.h>
-#include <assert.h>
-#include <errno.h>
 
 #ifdef CONFIG_PTHREAD_SPINLOCKS