RISC-V: Fix format specifier.

RISC-V: Fix format specifier.

Right now we get

../../gcc/config/riscv/riscv.cc: In function ‘bool riscv_check_target_clone_version(string_slice, location_t*)’:
../../gcc/config/riscv/riscv.cc:15078:17: warning: unknown conversion type character ‘B’ in format [-Wformat=]
15078 |                 "invalid version %qB for %<target_clones%> attribute",
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../gcc/config/riscv/riscv.cc:15078:17: warning: too many arguments for format [-Wformat-extra-args]

with a GCC 15 host compiler.

This patch replaces %qB with $<%.*s%>.

gcc/ChangeLog:

	* config/riscv/riscv.cc (riscv_check_target_clone_version): Fix
	format specifier.