riscv: Include single-letter extensions in isa_info_arr[]

Currently, the isa_info_arr[] only include multi-letter extensions but
the KVM ONE_REG interface covers both single-letter and multi-letter
extensions so extend isa_info_arr[] to include single-letter extensions.

This also allows combining two loops in the generate_cpu_nodes()
function into one loop.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20250426110348.338114-9-apatel@ventanamicro.com
Signed-off-by: Will Deacon <will@kernel.org>
1 file changed