x86: rename mp_config_table to mpc_table

Impact: cleanup, solve 80 columns wrap problems

mp_config_table should be renamed to mpc_table.
The reason: the 'c' in MPC already means 'config' -
no need to repeat that in the type name.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>