regmap: cache: rbtree: use krealloc_array() to replace krealloc()

Use krealloc_array() to replace krealloc() with multiplication.
krealloc_array() has multiply overflow check, which will be safer.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20241121123439.4180167-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>