mfd: syscon: Free the allocated name field of struct regmap_config

The commit 529a1101("mfd: syscon: Don't free allocated name
for regmap_config") doesn't free the allocated name field of struct
regmap_config, but introduce a memory leak. There is another
commit 94cc89eb("regmap: debugfs: Fix handling of name string
for debugfs init delays") fixing this debugfs init issue from root
cause. With this fixing, the name field in struct regmap_debugfs_node
is removed. When initialize debugfs for syscon driver, the name
field of struct regmap_config is not used anymore. So, the allocated
name field of struct regmap_config is need to be freed directly after
regmap initialization to avoid memory leak.

Cc: stable@vger.kernel.org
Fixes: 529a1101("mfd: syscon: Don't free allocated name for regmap_config")
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>