swscale/x86/swscale: Remove unused ASM constants

The last user of g15Mask, r15Mask, g16Mask and r16Mask was disabled
in 77a416e8 and finally removed in
36e8de07; b15Mask and b16Mask were
apparently always unused (except for in_asm_used_var_warning_killer,
a function that only existed to make the compiler not optimize ASM
constants away).
w10 is unused since d604bab9, w02
since ef423a66.
Signed-off-by: NAndreas Rheinhardt <andreas.rheinhardt@gmail.com>

libswscale/x86/swscale.c

@@ -44,15 +44,6 @@ const DECLARE_ALIGNED(8, uint64_t, ff_dither8)[2] = {
 
 DECLARE_ASM_CONST(8, uint64_t, bF8)=       0xF8F8F8F8F8F8F8F8LL;
 DECLARE_ASM_CONST(8, uint64_t, bFC)=       0xFCFCFCFCFCFCFCFCLL;
-DECLARE_ASM_CONST(8, uint64_t, w10)=       0x0010001000100010LL;
-DECLARE_ASM_CONST(8, uint64_t, w02)=       0x0002000200020002LL;
-
-DECLARE_ASM_CONST(8, uint64_t, b16Mask)=   0x001F001F001F001FLL;
-DECLARE_ASM_CONST(8, uint64_t, g16Mask)=   0x07E007E007E007E0LL;
-DECLARE_ASM_CONST(8, uint64_t, r16Mask)=   0xF800F800F800F800LL;
-DECLARE_ASM_CONST(8, uint64_t, b15Mask)=   0x001F001F001F001FLL;
-DECLARE_ASM_CONST(8, uint64_t, g15Mask)=   0x03E003E003E003E0LL;
-DECLARE_ASM_CONST(8, uint64_t, r15Mask)=   0x7C007C007C007C00LL;
 
 DECLARE_ASM_ALIGNED(8, const uint64_t, ff_M24A)         = 0x00FF0000FF0000FFLL;
 DECLARE_ASM_ALIGNED(8, const uint64_t, ff_M24B)         = 0xFF0000FF0000FF00LL;