x86: consolidate x86_64 architecture, SoC and boards

There are two set of code supporting x86_64: x86_64 using x32 ABI,
and x86 long mode, and this consolidates both into one x86_64
architecture and SoC supporting truly 64-bit mode.

() Removes the x86_64:x32 architecture and SoC, and replaces
   them with the existing x86 long mode arch and SoC.
() Replace qemu_x86_64 with qemu_x86_long as qemu_x86_64.
() Updates samples and tests to remove reference to
   qemu_x86_long.
() Renames CONFIG_X86_LONGMODE to CONFIG_X86_64.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

boards/x86/qemu_x86/Kconfig.board

@@ -7,8 +7,8 @@ config BOARD_QEMU_X86
 	select CPU_HAS_FPU
 	select HAS_COVERAGE_SUPPORT
 
-config BOARD_QEMU_X86_LONG
-	bool "QEMU x86 (64-bit long mode)"
+config BOARD_QEMU_X86_64
+	bool "QEMU x86_64"
 	depends on SOC_IA32
 	select QEMU_TARGET
-	select X86_LONGMODE
+	select X86_64

boards/x86/qemu_x86/Kconfig.defconfig

@@ -17,9 +17,9 @@ endif
 
 endif # BOARD_QEMU_X86
 
-if BOARD_QEMU_X86_LONG
+if BOARD_QEMU_X86_64
 
 config BOARD
-	default "qemu_x86_long"
+	default "qemu_x86_64"
 
-endif # BOARD_QEMU_X86_LONG
+endif # BOARD_QEMU_X86_64

boards/x86/qemu_x86/board.cmake

@@ -6,7 +6,7 @@ if(NOT CONFIG_REBOOT)
   set(REBOOT_FLAG -no-reboot)
 endif()
 
-if(CONFIG_X86_LONGMODE)
+if(CONFIG_X86_64)
   set(QEMU_binary_suffix x86_64)
   set(QEMU_CPU_TYPE_${ARCH} qemu64,+x2apic)
 else()

boards/x86/qemu_x86/qemu_x86_64.yaml

@@ -1,5 +1,5 @@
-identifier: qemu_x86_long
-name: QEMU Emulation for X86 (long mode)
+identifier: qemu_x86_64
+name: QEMU Emulation for X86_64
 type: qemu
 arch: x86
 toolchain:

boards/x86/qemu_x86/qemu_x86_64_defconfig

@@ -2,7 +2,7 @@
 
 CONFIG_X86=y
 CONFIG_SOC_IA32=y
-CONFIG_BOARD_QEMU_X86_LONG=y
+CONFIG_BOARD_QEMU_X86_64=y
 CONFIG_CPU_MINUTEIA=y
 CONFIG_HPET_TIMER=y
 CONFIG_PIC_DISABLE=y