random: make consistent use of buf and len

The current code was a mix of "nbytes", "count", "size", "buffer", "in",
and so forth. Instead, let's clean this up by naming input parameters
"buf" (or "ubuf") and "len", so that you always understand that you're
reading this variety of function argument.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

include/linux/random.h

@@ -12,12 +12,12 @@
 
 struct notifier_block;
 
-void add_device_randomness(const void *, size_t);
-void add_bootloader_randomness(const void *, size_t);
+void add_device_randomness(const void *buf, size_t len);
+void add_bootloader_randomness(const void *buf, size_t len);
 void add_input_randomness(unsigned int type, unsigned int code,
 			  unsigned int value) __latent_entropy;
 void add_interrupt_randomness(int irq) __latent_entropy;
-void add_hwgenerator_randomness(const void *buffer, size_t count, size_t entropy);
+void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy);
 
 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
 static inline void add_latent_entropy(void)
@@ -29,7 +29,7 @@ static inline void add_latent_entropy(void) { }
 #endif
 
 #if IS_ENABLED(CONFIG_VMGENID)
-void add_vmfork_randomness(const void *unique_vm_id, size_t size);
+void add_vmfork_randomness(const void *unique_vm_id, size_t len);
 int register_random_vmfork_notifier(struct notifier_block *nb);
 int unregister_random_vmfork_notifier(struct notifier_block *nb);
 #else
@@ -37,8 +37,8 @@ static inline int register_random_vmfork_notifier(struct notifier_block *nb) { r
 static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
 #endif
 
-void get_random_bytes(void *buf, size_t nbytes);
-size_t __must_check get_random_bytes_arch(void *buf, size_t nbytes);
+void get_random_bytes(void *buf, size_t len);
+size_t __must_check get_random_bytes_arch(void *buf, size_t len);
 u32 get_random_u32(void);
 u64 get_random_u64(void);
 static inline unsigned int get_random_int(void)