powerpc/pasemi: Use strscpy instead of strlcpy

find_i2c_driver() contained the last usage of strlcpy() in arch/powerpc.
The return value was used to check if strlen(src) >= n, for which
strscpy() returns -E2BIG.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220827063946.9073-1-ruscur@russell.cc