x86/mce/amd: Remove smca_banks_map

x86/mce/amd: Remove smca_banks_map

The MCx_MISC0[BlkPtr] field was used on legacy systems to hold a register
offset for the next MCx_MISC* register. In this way, an implementation-specific
number of registers can be discovered at runtime.

The MCAX/SMCA register space simplifies this by always including the
MCx_MISC[1-4] registers. The MCx_MISC0[BlkPtr] field is used to indicate
(true/false) whether any MCx_MISC[1-4] registers are present.

Currently, MCx_MISC0[BlkPtr] is checked early and cached to be used during
sysfs init later. This is unnecessary as the MCx_MISC0 register is read again
later anyway.

Remove the smca_banks_map variable as it is effectively redundant, and use
a direct register/bit check instead.

  [ bp: Zap smca_get_block_address() too. ]

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/20250825-wip-mca-updates-v5-3-865768a2eef8@amd.com