powerpc: mpc8xxx: Extend find_law() to find_law_by_addr_id()

powerpc: mpc8xxx: Extend find_law() to find_law_by_addr_id()

The find_law() function searches for LAW just by physical address. This
is unsuitable for cases with overlapping LAWs. Extend it to
find_law_by_addr_id(), which searches for LAW by physical address and
target id.

Add a static inline definition of the original find_law() into fsl_law.h
header.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Mojík <marek.mojik@nic.cz>
Reviewed-by: Marek Behún <kabel@kernel.org>