target/mips: Remove unused mips_def_t::SAARP field

The SAARP field added in commit 5fb2dcd179 ("target/mips: Provide
R/W access to SAARI and SAAR CP0 registers") has never been used,
remove it.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240215080629.51190-1-philmd@linaro.org>

target/mips/internal.h

@@ -83,7 +83,6 @@ struct mips_def_t {
     uint32_t lcsr_cpucfg2;
     uint64_t insn_flags;
     enum mips_mmu_types mmu_type;
-    int32_t SAARP;
 };
 
 extern const char regnames[32][3];