arm64: signal: Remove unused macro

Commit 33f0826 ("arm64: signal: Allow expansion of the signal
frame") introduced the BASE_SIGFRAME_SIZE macro but it has
apparently never been used; just remove it.

Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://lore.kernel.org/r/20241029144539.111155-4-kevin.brodsky@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: kevin-brodsky-arm

arch/arm64/kernel/signal.c

@@ -79,7 +79,6 @@ struct user_access_state {
 	u64 por_el0;
 };
 
-#define BASE_SIGFRAME_SIZE round_up(sizeof(struct rt_sigframe), 16)
 #define TERMINATOR_SIZE round_up(sizeof(struct _aarch64_ctx), 16)
 #define EXTRA_CONTEXT_SIZE round_up(sizeof(struct extra_context), 16)