security/nettle: fix build on powerpc64*

Due to the string "swap_mask" being replaced with the vector register,
the assembly label pointing at the local data variable .swap_mask was
being replaced as well, causing the local label to be named ".0", which
the clang integrated assembler treats as a syntax error.

Change the name to .swap_data.

Submitted by: bdragon

security/nettle/patch-powerpc64-p8-aes-decrypt-internal.asm

@@ -0,0 +1,19 @@
+--- powerpc64/p8/aes-decrypt-internal.asm.orig	2021-04-03 16:33:37.883035000 -0500
++++ powerpc64/p8/aes-decrypt-internal.asm	2021-04-03 16:34:24.022307000 -0500
+@@ -71,7 +71,7 @@ define(`FUNC_ALIGN', `5')
+ PROLOGUE(_nettle_aes_decrypt)
+  vxor ZERO,ZERO,ZERO
+
+- DATA_LOAD_VEC(swap_mask,.swap_mask,r5)
++ DATA_LOAD_VEC(swap_mask,.swap_data,r5)
+
+  subi ROUNDS,ROUNDS,1
+  srdi LENGTH,LENGTH,4
+@@ -351,6 +351,6 @@ EPILOGUE(_nettle_aes_decrypt)
+
+  .data
+  .align 4
+-.swap_mask:
++.swap_data:
+ IF_LE(`.byte 8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7')
+ IF_BE(`.byte 3,2,1,0,7,6,5,4,11,10,9,8,15,14,13,12')

security/nettle/patch-powerpc64-p8-aes-encrypt-internal.asm

@@ -0,0 +1,19 @@
+--- powerpc64/p8/aes-encrypt-internal.asm.orig	2021-04-03 16:33:26.104735000 -0500
++++ powerpc64/p8/aes-encrypt-internal.asm	2021-04-03 16:34:43.805790000 -0500
+@@ -63,7 +63,7 @@ define(`S7', `v9')
+
+ define(`FUNC_ALIGN', `5')
+ PROLOGUE(_nettle_aes_encrypt)
+- DATA_LOAD_VEC(swap_mask,.swap_mask,r5)
++ DATA_LOAD_VEC(swap_mask,.swap_data,r5)
+
+  subi ROUNDS,ROUNDS,1
+  srdi LENGTH,LENGTH,4
+@@ -328,6 +328,6 @@ EPILOGUE(_nettle_aes_encrypt)
+
+  .data
+  .align 4
+-.swap_mask:
++.swap_data:
+ IF_LE(`.byte 8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7')
+ IF_BE(`.byte 3,2,1,0,7,6,5,4,11,10,9,8,15,14,13,12')