[scudo] Avoid deprecated-volatile warning in HybridMutex::delayLoop (#67135)

That can prevent compilation with -Werror and -std=c++20:
mutex.h:63:7: error: increment of object of volatile-qualified type 'volatile u32' (aka 'volatile unsigned int') is deprecated [-Werror,-Wdeprecated-volatile]

GitOrigin-RevId: 2f91751daef168ff1959ad1df2d64d7bea6b3152
1 file changed