sh: fix incorrect mcontext_t member naming

while the layouts match, the member member naming expected by software
using mcontext_t omits the sc_ prefix.

arch/sh/bits/signal.h

@@ -9,7 +9,16 @@
 #if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
 typedef int greg_t, gregset_t[16];
 typedef int freg_t, fpregset_t[16];
-typedef struct sigcontext {
+typedef struct {
+	unsigned long oldmask;
+	unsigned long gregs[16];
+	unsigned long pc, pr, sr;
+	unsigned long gbr, mach, macl;
+	unsigned long fpregs[16];
+	unsigned long xfpregs[16];
+	unsigned int fpscr, fpul, ownedfp;
+} mcontext_t;
+struct sigcontext {
 	unsigned long oldmask;
 	unsigned long sc_regs[16];
 	unsigned long sc_pc, sc_pr, sc_sr;
@@ -17,7 +26,7 @@ typedef struct sigcontext {
 	unsigned long sc_fpregs[16];
 	unsigned long sc_xfpregs[16];
 	unsigned int sc_fpscr, sc_fpul, sc_ownedfp;
-} mcontext_t;
+};
 #else
 typedef struct {
 	unsigned long __regs[58];

arch/sh/pthread_arch.h

@@ -8,9 +8,9 @@ static inline uintptr_t __get_tp()
 #define TLS_ABOVE_TP
 #define GAP_ABOVE_TP 8
 
-#define MC_PC sc_pc
+#define MC_PC pc
 
 #ifdef __FDPIC__
-#define MC_GOT sc_regs[12]
+#define MC_GOT gregs[12]
 #define CANCEL_GOT (*(uintptr_t *)((char *)__syscall_cp_asm+sizeof(uintptr_t)))
 #endif