sr: Remove in_interrupt() usage in sr_init_command().

sr: Remove in_interrupt() usage in sr_init_command().

The in_interrupt() check in sr_init_command() is a leftover from the
past, pre v2.3.16 era to be exact. Back then the ioctl() was served by
`sr' itself and sector size changes by CDROMREADMODE2 (as noted in the
comment) were accounted within sr's data structures which allowed a
"lazy" reset so it could be skipped on the next request and reset back
to the default value once the device node was closed or before a command
from the blockqueue was issued.

This does not work like that anymore. The CDROMREADMODE2 is served by
cdrom's mmc_ioctl() function which may change the sector size but the
`sr' driver does not learn about it and so its ->sector_size is not
updated.
The ioctl() resets the changed sector size back to 2048.
sr_read_sector() also resets the sector size back to the default once it
is done.

Remove the conditional sector size update from sr_init_command() and
sr_release() because it is not needed.

Link: https://lkml.kernel.org/r/20201204164803.ovwurzs3257em2rp@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>