fix build with armv6  Error: .size expression for _vpaes_decrypt_consts does not evaluate to a constant

Before change cross compiling with https://sourceforge.net/projects/raspberry-pi-cross-compilers/files/Raspberry%20Pi%20GCC%20Cross-Compiler%20Toolchains/GCC%209.1.0/Raspberry%20Pi%201%2C%20Zero/cross-gcc-9.1.0-pi_0-1.tar.gz
 fails
arm-linux-gnueabihf-gcc  -march=armv6 -mfloat-abi=hard -mfpu=vfp -marm -c vpaes-armv7.S -o vpaes-armv7.o
/tmp/cctW8fgE.s: Assembler messages:
/tmp/cctW8fgE.s: Error: .size expression for _vpaes_decrypt_consts does not evaluate to a constant

Bug: 291
Change-Id: Ib2bf608943bbb406b33181a75f1ade2c4bab09ba
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/37824
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
diff --git a/crypto/fipsmodule/aes/asm/vpaes-armv7.pl b/crypto/fipsmodule/aes/asm/vpaes-armv7.pl
index deb9a2a..12b5828 100644
--- a/crypto/fipsmodule/aes/asm/vpaes-armv7.pl
+++ b/crypto/fipsmodule/aes/asm/vpaes-armv7.pl
@@ -335,6 +335,7 @@
 @
 .type	_vpaes_decrypt_consts,%object
 .align	4
+_vpaes_decrypt_consts:
 .Lk_dipt:	@ decryption input transform
 	.quad	0x0F505B040B545F00, 0x154A411E114E451A
 	.quad	0x86E383E660056500, 0x12771772F491F194