misc: amd-sbi: Add support for read MCA register protocol

misc: amd-sbi: Add support for read MCA register protocol

- AMD provides custom protocol to read Machine Check Architecture(MCA)
  registers over sideband. The information is accessed for range of
  MCA registers by passing register address and thread ID to the protocol.
  MCA register read command using the register address to access
  Core::X86::Msr::MCG_CAP which determines the number of MCA banks.
  Access is read-only

Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
Link: https://lore.kernel.org/r/20250428063034.2145566-9-akshay.gupta@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>