avutil/x86/asm: rename REG_SP to REG_sp

REG_SP is defined by Solaris system headers.
This fixes a sea of warnings while building on Solaris:
http://fate.ffmpeg.org/report.cgi?time=20150820233505&slot=x86-opensolaris-gcc4.3Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavutil/x86/asm.h

@@ -38,7 +38,8 @@ typedef struct ymm_reg { uint64_t a, b, c, d; } ymm_reg;
 #    define PTR_SIZE "8"
 typedef int64_t x86_reg;
 
-#    define REG_SP "rsp"
+/* REG_SP is defined in Solaris sys headers, so use REG_sp */
+#    define REG_sp "rsp"
 #    define REG_BP "rbp"
 #    define REGBP   rbp
 #    define REGa    rax
@@ -59,7 +60,7 @@ typedef int64_t x86_reg;
 #    define PTR_SIZE "4"
 typedef int32_t x86_reg;
 
-#    define REG_SP "esp"
+#    define REG_sp "esp"
 #    define REG_BP "ebp"
 #    define REGBP   ebp
 #    define REGa    eax

libpostproc/postprocess_template.c

@@ -1317,7 +1317,7 @@ DERING_CORE((%0, %1, 8)    ,(%%REGd, %1, 4),%%mm2,%%mm4,%%mm0,%%mm3,%%mm5,%%mm1,
         "1:                        \n\t"
         : : "r" (src), "r" ((x86_reg)stride), "m" (c->pQPb), "m"(c->pQPb2), "q"(tmp)
           NAMED_CONSTRAINTS_ADD(deringThreshold,b00,b02,b08)
-        : "%"REG_a, "%"REG_d, "%"REG_SP
+        : "%"REG_a, "%"REG_d, "%"REG_sp
     );
 #else // HAVE_7REGS && (TEMPLATE_PP_MMXEXT || TEMPLATE_PP_3DNOW)
     int y;