asm: start x86 intrinsics examples

Split userland/arch/<arch>/c/ into inline_asm and intrinsics, and move programs
that don't match either up.

userland/arch/arm/inline_asm/freestanding/linux/build

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+../build

userland/arch/arm/inline_asm/freestanding/linux/hello.c

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+/* https://github.com/cirosantilli/linux-kernel-module-cheat#linux-system-calls
+ *
+ * arm freestanding C inline assemby Linux hello world.
+ */
+
+#include <inttypes.h>
+
+void _start(void) {
+    uint32_t exit_status;
+
+    /* write */
+    {
+        char msg[] = "hello\n";
+        uint32_t syscall_return;
+        register uint32_t r0 __asm__ ("r0") = 1; /* stdout */
+        register char *r1 __asm__ ("r1") = msg;
+        register uint32_t r2 __asm__ ("r2") = sizeof(msg);
+        register uint32_t r8 __asm__ ("r7") = 4; /* syscall number */
+        __asm__ __volatile__ (
+            "svc 0;"
+            : "+r" (r0)
+            : "r" (r1), "r" (r2), "r" (r8)
+            : "memory"
+        );
+        syscall_return = r0;
+        exit_status = (syscall_return != sizeof(msg));
+    }
+
+    /* exit */
+    {
+        register uint32_t r0 __asm__ ("r0") = exit_status;
+        register uint32_t r7 __asm__ ("r7") = 1;
+        __asm__ __volatile__ (
+            "svc 0;"
+            : "+r" (r0)
+            : "r" (r7)
+            :
+        );
+    }
+}

userland/arch/arm/inline_asm/freestanding/linux/test

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+../test