i2c: sun6i-pw2i: Prefer strscpy over strlcpy

i2c: sun6i-pw2i: Prefer strscpy over strlcpy

strlcpy() reads the entire source buffer first. This read may exceed the
destination size limit. This is both inefficient and can lead to linear
read overflows if a source string is not NUL-terminated. The safe
replacement is strscpy().

This is a previous step in the path to remove the strlcpy() function
entirely from the kernel [1].

[1] https://github.com/KSPP/linux/issues/89

Signed-off-by: Len Baker <len.baker@gmx.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>