tree: Consolidate BIT() macro

Change-Id: I7e61f7671b70ca5ed751d99405714436bcd18d5a
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/64962
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>

include/flash.h

@@ -39,6 +39,8 @@
 #define KiB (1024)
 #define MiB (1024 * KiB)
 
+#define BIT(x) (1<<(x))
+
 /* Assumes `n` and `a` are at most 64-bit wide (to avoid typeof() operator). */
 #define ALIGN_DOWN(n, a) ((n) & ~((uint64_t)(a) - 1))