riscv: Explicitly specify the build id style in vDSO Makefile again

Commit a9684337 ("kbuild: explicitly specify the build id style")
explicitly set the build ID style to SHA1. Commit c2c81bb2 ("RISC-V:
Fix the VDSO symbol generaton for binutils-2.35+") undid this change,
likely unintentionally.

Restore it so that the build ID style stays consistent across the tree
regardless of linker.

Fixes: c2c81bb2 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+")
Signed-off-by: NNathan Chancellor <natechancellor@gmail.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Reviewed-by: NBill Wendling <morbo@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/kernel/vdso/Makefile

@@ -44,7 +44,7 @@ SYSCFLAGS_vdso.so.dbg = $(c_flags)
 $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
 	$(call if_changed,vdsold)
 SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
-	-Wl,--build-id -Wl,--hash-style=both
+	-Wl,--build-id=sha1 -Wl,--hash-style=both
 
 # We also create a special relocatable object that should mirror the symbol
 # table and layout of the linked DSO. With ld --just-symbols we can then