alpha: math-emu: Fix modular build

Commit 00fc0e0dda62 ("alpha: move exports to actual definitions") also
removed the exports of the math emulator hooks, which are defined in C
code. In case anyone cares about the option of CONFIG_MATHEMU=m, add
exports next to those definitions. Also add a MODULE_LICENSE.

Fixes: 00fc0e0dda62 ("alpha: move exports to actual definitions")
Signed-off-by: Ben Hutchings <[e-mail]>
Signed-off-by: Matt Turner <[e-mail]>

arch/alpha/kernel/traps.c

···
 static long dummy_emul(void) { return 0; }
 long (*alpha_fp_emul_imprecise)(struct pt_regs *regs, unsigned long writemask)
   = (void *)dummy_emul;
+EXPORT_SYMBOL_GPL(alpha_fp_emul_imprecise);
 long (*alpha_fp_emul) (unsigned long pc)
   = (void *)dummy_emul;
+EXPORT_SYMBOL_GPL(alpha_fp_emul);
 #else
 long alpha_fp_emul_imprecise(struct pt_regs *regs, unsigned long writemask);
 long alpha_fp_emul (unsigned long pc);

arch/alpha/math-emu/math.c

···
 #ifdef MODULE
 
 MODULE_DESCRIPTION("FP Software completion module");
+MODULE_LICENSE("GPL v2");
 
 extern long (*alpha_fp_emul_imprecise)(struct pt_regs *, unsigned long);
 extern long (*alpha_fp_emul) (unsigned long pc);