x86/fpu: Clean up the parameter definitions of copy_xstate_to_*()

Remove pointless 'const' of non-pointer input parameter.

Remove unnecessary parenthesis that shows uncertainty about arithmetic operator precedence.

Clarify copy_xstate_to_user() description.

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-7-mingo@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/fpu/xstate.c

@@ -927,13 +927,13 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 static inline int
 __copy_xstate_to_kernel(void *kbuf,
 			const void *data,
-			unsigned int pos, unsigned int count, const int start_pos, const int end_pos)
+			unsigned int pos, unsigned int count, int start_pos, int end_pos)
 {
 	if ((count == 0) || (pos < start_pos))
 		return 0;
 
 	if (end_pos < 0 || pos < end_pos) {
-		unsigned int copy = (end_pos < 0 ? count : min(count, end_pos - pos));
+		unsigned int copy = end_pos < 0 ? count : min(count, end_pos - pos);
 
 		memcpy(kbuf + pos, data, copy);
 	}
@@ -1010,13 +1010,13 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int po
 }
 
 static inline int
-__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, unsigned int count, const int start_pos, const int end_pos)
+__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, unsigned int count, int start_pos, int end_pos)
 {
 	if ((count == 0) || (pos < start_pos))
 		return 0;
 
 	if (end_pos < 0 || pos < end_pos) {
-		unsigned int copy = (end_pos < 0 ? count : min(count, end_pos - pos));
+		unsigned int copy = end_pos < 0 ? count : min(count, end_pos - pos);
 
 		if (__copy_to_user(ubuf + pos, data, copy))
 			return -EFAULT;
@@ -1026,7 +1026,7 @@ __copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int pos, uns
 
 /*
  * Convert from kernel XSAVES compacted format to standard format and copy
- * to a ptrace buffer. It supports partial copy but pos always starts from
+ * to a user-space buffer. It supports partial copy but pos always starts from
  * zero. This is called from xstateregs_get() and there we check the CPU
  * has XSAVES.
  */