[gcc(refs/vendors/riscv/heads/gcc-15-with-riscv-opts)] RISC-V: Drop duplicate build rule for riscv-ext.opt [NFC]

[Jeff Law]

https://gcc.gnu.org/g:dad42f9e2ede9b458172a51477ddf81c1938f83b

commit dad42f9e2ede9b458172a51477ddf81c1938f83b
Author: Kito Cheng <kito.cheng@sifive.com>
Date:   Wed May 14 23:19:38 2025 +0800

    RISC-V: Drop duplicate build rule for riscv-ext.opt [NFC]
    
    gcc/ChangeLog:
    
            * config/riscv/t-riscv: Drop duplicate build rule for
            riscv-ext.opt.
    
    (cherry picked from commit eedaf969f4d24dad368de63ea40b1e694fd57c40)

Diff:
---
 gcc/config/riscv/t-riscv | 2 --
 1 file changed, 2 deletions(-)

diff --git a/gcc/config/riscv/t-riscv b/gcc/config/riscv/t-riscv
index e99d6689ba06..854daa96e73c 100644
--- a/gcc/config/riscv/t-riscv
+++ b/gcc/config/riscv/t-riscv
@@ -198,8 +198,6 @@ RISCV_EXT_DEFS = \
 
 $(srcdir)/config/riscv/riscv-ext.opt: $(RISCV_EXT_DEFS)
 
-$(srcdir)/config/riscv/riscv-ext.opt: s-riscv-ext.opt ; @true
-
 build/gen-riscv-ext-opt$(build_exeext): $(srcdir)/config/riscv/gen-riscv-ext-opt.cc \
 	$(RISCV_EXT_DEFS)
 	$(CXX_FOR_BUILD) $(CXXFLAGS_FOR_BUILD) $< -o $@