lightnvm: move NVM_DEBUG to pblk

There is no users of CONFIG_NVM_DEBUG in the LightNVM subsystem. All
users are in pblk. Rename NVM_DEBUG to NVM_PBLK_DEBUG and enable
only for pblk.

Also fix up the CONFIG_NVM_PBLK entry to follow the code style for
Kconfig files.

Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/pblk.h

@@ -193,7 +193,7 @@ struct pblk_rb {
 	spinlock_t w_lock;		/* Write lock */
 	spinlock_t s_lock;		/* Sync lock */
 
-#ifdef CONFIG_NVM_DEBUG
+#ifdef CONFIG_NVM_PBLK_DEBUG
 	atomic_t inflight_flush_point;	/* Not served REQ_FLUSH | REQ_FUA */
 #endif
 };
@@ -636,7 +636,7 @@ struct pblk {
 	u64 nr_flush_rst;		/* Flushes reset value for pad dist.*/
 	atomic64_t nr_flush;		/* Number of flush/fua I/O */
 
-#ifdef CONFIG_NVM_DEBUG
+#ifdef CONFIG_NVM_PBLK_DEBUG
 	/* Non-persistent debug counters, 4kb sector I/Os */
 	atomic_long_t inflight_writes;	/* Inflight writes (user and gc) */
 	atomic_long_t padded_writes;	/* Sectors padded due to flush/fua */
@@ -1279,7 +1279,7 @@ static inline int pblk_io_aligned(struct pblk *pblk, int nr_secs)
 	return !(nr_secs % pblk->min_write_pgs);
 }
 
-#ifdef CONFIG_NVM_DEBUG
+#ifdef CONFIG_NVM_PBLK_DEBUG
 static inline void print_ppa(struct nvm_geo *geo, struct ppa_addr *p,
 			     char *msg, int error)
 {