x86/resctrl: Move max_{name,data}_width into resctrl code

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/snapshot/v6.7-rc2



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max_name_width and max_data_width are used to pad the strings in the
resctrl schemata file.

This should be part of the fs code as it influences the user-space
interface, but currently max_data_width is generated by the arch init code.
max_name_width is already managed by schemata_list_add().

Move the variables and max_data_width's initialisation code to rdtgroup.c.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Zeng Heng <zengheng4@huawei.com>