regmap: cache: Fix format specifier in dev_dbg

Fix format specifier in dev_dbg and suppress the following warning

drivers/base/regmap/regcache.c: In function
‘regcache_sync_block_raw_flush’:
drivers/base/regmap/regcache.c:593:2: warning: format ‘%d’ expects
argument of type ‘int’, but argument 4 has type ‘size_t’ [-Wformat]

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>