linux-user/sparc: Use WREG_SP constant in sparc/signal.c

s/UREG_FP/WREG_SP/g

This is non-obvious because the UREG_FP constant is fact wrong.
However, the previous search-and-replace patch made it clear that
UREG_FP expands to WREG_O6, and we can see from the enumeration in
target/sparc/cpu.h that WREG_O6 is in fact WREG_SP, the stack pointer.

The UREG_SP define is unused; remove it.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20191106113318.10226-7-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/sparc/signal.c

@@ -104,9 +104,6 @@ struct target_rt_signal_frame {
     qemu_siginfo_fpu_t  fpu_state;
 };
 
-#define UREG_FP        WREG_O6
-#define UREG_SP        WREG_I6
-
 static inline abi_ulong get_sigframe(struct target_sigaction *sa, 
                                      CPUSPARCState *env,
                                      unsigned long framesize)
@@ -201,7 +198,7 @@ void setup_frame(int sig, struct target_sigaction *ka,
         goto sigsegv;
 
     /* 3. signal handler back-trampoline and parameters */
-    env->regwptr[UREG_FP] = sf_addr;
+    env->regwptr[WREG_SP] = sf_addr;
     env->regwptr[WREG_O0] = sig;
     env->regwptr[WREG_O1] = sf_addr +
             offsetof(struct target_signal_frame, info);
@@ -255,7 +252,7 @@ long do_sigreturn(CPUSPARCState *env)
     sigset_t host_set;
     int i;
 
-    sf_addr = env->regwptr[UREG_FP];
+    sf_addr = env->regwptr[WREG_SP];
     trace_user_do_sigreturn(env, sf_addr);
     if (!lock_user_struct(VERIFY_READ, sf, sf_addr, 1)) {
         goto segv_and_exit;