BareMetal: Add support for M68K architecture in GCC toolchain

This commit adds support for the M68K atchitecture:

 * https://en.wikipedia.org/wiki/Motorola_68000_series

using GCC toolchains.

Tested auto-detection on Windows using the GCC v4.8.0 toolchain
provided from the following URL:

 * https://gnutoolchains.com/m68k-elf/

Change-Id: I5f1e36de240f3f53b54e0e6a8edb318746d345e7
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/abi.cpp

@@ -517,6 +517,12 @@ Abi Abi::abiFromTargetTriplet(const QString &triple)
             flavor = GenericFlavor;
             format = ElfFormat;
             width = 32;
+        } else if (p == "m68k") {
+            arch = M68KArchitecture;
+            os = BareMetalOS;
+            flavor = GenericFlavor;
+            format = ElfFormat;
+            width = 16;
         } else if (p.startsWith("riscv")) {
             arch = RiscVArchitecture;
             os = BareMetalOS;