regmap: use int type to store negative error codes

regmap: use int type to store negative error codes

Change the 'ret' variable from unsigned int to int to store negative error
codes or zero returned by regmap_field_read() and regmap_read(), and change
'-1' to 'negative errno' in the comments.

Storing the negative error codes in unsigned type, doesn't cause an issue
at runtime but it's ugly as pants. Additionally, assigning negative error
codes to unsigned type may trigger a GCC warning when the -Wsign-conversion
flag is enabled.

No effect on runtime.

Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Message-ID: <20250828150702.193288-1-rongqianfeng@vivo.com>
Signed-off-by: Mark Brown <broonie@kernel.org>