ide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings (e.g.
"unused variable"). If the compiler thinks it is uninitialized, either
simply initialize the variable or make compiler changes. As a precursor
to removing[2] this[3] macro[4], just remove this variable since it was
actually unused:

drivers/ide/ide-taskfile.c:232:34: warning: unused variable 'flags' [-Wunused-variable]
        unsigned long uninitialized_var(flags);
                                        ^

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Fixes: ce1e518190 ("ide: don't disable interrupts during kmap_atomic()")
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

drivers/ide/ide-taskfile.c

@@ -229,7 +229,6 @@ void ide_pio_bytes(ide_drive_t *drive, struct ide_cmd *cmd,
 	ide_hwif_t *hwif = drive->hwif;
 	struct scatterlist *sg = hwif->sg_table;
 	struct scatterlist *cursg = cmd->cursg;
-	unsigned long uninitialized_var(flags);
 	struct page *page;
 	unsigned int offset;
 	u8 *buf;