riscv: Define AT_VECTOR_SIZE_ARCH for ARCH_DLINFO

AT_VECTOR_SIZE_ARCH should be defined with the maximum number of
NEW_AUX_ENT entries that ARCH_DLINFO can contain, but it wasn't defined
for RISC-V at all even though ARCH_DLINFO will contain one NEW_AUX_ENT
for the VDSO address.
Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/include/uapi/asm/auxvec.h

@@ -10,4 +10,7 @@
 /* vDSO location */
 #define AT_SYSINFO_EHDR 33
 
+/* entries in ARCH_DLINFO */
+#define AT_VECTOR_SIZE_ARCH	1
+
 #endif /* _UAPI_ASM_RISCV_AUXVEC_H */