vdso: Address variable shadowing in macros

Compiling the kernel with gcc12.3 W=2 results in shadowing warnings:

warning: declaration of '__pptr' shadows a previous local [-Wshadow]
  const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);

note: in definition of macro '__put_unaligned_t'
  __pptr->x = (val);

note: in expansion of macro '__get_unaligned_t'
  __put_unaligned_t(type, __get_unaligned_t(type, src), dst);

__get_unaligned_t() and __put_unaligned_t() use a local variable named
'__pptr', which can lead to variable shadowing when these macros are used in
the same scope. This results in a -Wshadow warning during compilation.

To address this issue, rename the local variables within the macros to
ensure uniqueness.

Signed-off-by: Peng Jiang <jiang.peng9@zte.com.cn>
Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250324191230477zpGtgIRSH4mEHdtxGtgx9@zte.com.cn

Author: Jump2233

include/vdso/unaligned.h

@@ -2,14 +2,14 @@
 #ifndef __VDSO_UNALIGNED_H
 #define __VDSO_UNALIGNED_H
 
-#define __get_unaligned_t(type, ptr) ({						\
-	const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);	\
-	__pptr->x;								\
+#define __get_unaligned_t(type, ptr) ({							\
+	const struct { type x; } __packed * __get_pptr = (typeof(__get_pptr))(ptr);	\
+	__get_pptr->x;									\
 })
 
-#define __put_unaligned_t(type, val, ptr) do {					\
-	struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);		\
-	__pptr->x = (val);							\
+#define __put_unaligned_t(type, val, ptr) do {						\
+	struct { type x; } __packed * __put_pptr = (typeof(__put_pptr))(ptr);		\
+	__put_pptr->x = (val);								\
 } while (0)
 
 #endif /* __VDSO_UNALIGNED_H */