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/aarch64/inline_asm/inc_float.c

@@ -0,0 +1,25 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#gcc-inline-assembly-floating-point-arm */
+
+#include <assert.h>
+
+int main(void) {
+    float my_float = 1.5;
+    __asm__ (
+        "fmov s0, 1.0;"
+        "fadd %s[my_float], %s[my_float], s0;"
+        : [my_float] "+w" (my_float)
+        :
+        : "s0"
+    );
+    assert(my_float == 2.5);
+
+    double my_double = 1.5;
+    __asm__ (
+        "fmov d0, 1.0;"
+        "fadd %d[my_double], %d[my_double], d0;"
+        : [my_double] "+w" (my_double)
+        :
+        : "d0"
+    );
+    assert(my_double == 2.5);
+}