[SDK:CMAKE] Remove unused BUILD_MP build option (#7862)

It was introduced in commit 1f9c4940 (r38270), but this flag isn't used anymore in our source tree, and nowadays, we actively compile both UP and MP support.

[SDK:CMAKE] Remove unused BUILD_MP build option (#7862)
It was introduced in commit 1f9c4940 (r38270), but this flag isn't used anymore in our source tree, and nowadays, we actively compile both UP and MP support.
79f281e7 · Hermès Bélusca-Maïto · 00f4a0f8 · 79f281e7
--- a/sdk/cmake/config.cmake
+++ b/sdk/cmake/config.cmake
@@ -92,8 +92,6 @@ else()
    set(_WINKD_ FALSE CACHE BOOL "Whether to compile with the KD protocol.")
 endif()

-option(BUILD_MP "Whether to build the multiprocessor versions of NTOSKRNL and HAL." ON)
-
 cmake_dependent_option(ISAPNP_ENABLE "Whether to enable the ISA PnP support." ON
                       "ARCH STREQUAL i386 AND NOT SARCH STREQUAL xbox" OFF)