MdeModulePkg/SmbiosDxe: Fix pointer and buffer overflow CodeQL alerts

Details for these CodeQL alerts can be found here:

- Pointer overflow check (cpp/pointer-overflow-check):
  - https://cwe.mitre.org/data/definitions/758.html

- Potential buffer overflow check (cpp/potential-buffer-overflow):
  - https://cwe.mitre.org/data/definitions/676.html



CodeQL alert:

  - Line 1612 in MdeModulePkg/Universal/SmbiosDxe/SmbiosDxe.c
    - Type: Pointer overflow check
    - Severity: Low
    - Problem: Range check relying on pointer overflow

Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Erich McMillan <emcmillan@microsoft.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Michael Kubacki <mikuback@linux.microsoft.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Co-authored-by: Michael Kubacki <michael.kubacki@microsoft.com>
Signed-off-by: Erich McMillan <emcmillan@microsoft.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Oliver Smith-Denny <osd@smith-denny.com>