spmi: pmic-arb: fix memory allocation for mapping_table

Allocate the correct memory size (max_pmic_peripherals) for the
mapping_table that holds the apid to ppid mapping. Also use a local
variable for mapping_table for better alignment of the code.

Fixes: 987a9f12 ("spmi: pmic-arb: Support more than 128 peripherals")
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>