feat: small code optimisations

kernel/vfs/lfs/ext2.c

@@ -17,7 +17,6 @@
 #define EXT2_DRIVER_NAME "ext2"
 #define MI(mount) ((ext2_mount_info_t *)(mount)->global_driver_data)
 #define FDI(fd) ((ext2_fd_info_t *)(fd)->driver_data)
-#define DIV_ROUND_UP(a, b) (((a) + ((b) - 1)) / (b))
 
 typedef struct ext2_dgetents_state {
     uint32_t bp;