Documentation: Fix description format for powerpc RTAS ioctls

Documentation: Fix description format for powerpc RTAS ioctls

Fix the description format for the following build warnings:

"Documentation/userspace-api/ioctl/ioctl-number.rst:369:
ERROR: Malformed table. Text in column margin in table line 301.

0xB2  03-05 arch/powerpc/include/uapi/asm/papr-indices.h
powerpc/pseries indices API
                            <mailto:linuxppc-dev>
0xB2  06-07 arch/powerpc/include/uapi/asm/papr-platform-dump.h
powerpc/pseries Platform Dump API
                            <mailto:linuxppc-dev>
0xB2  08  arch/powerpc/include/uapi/asm/papr-physical-attestation.h
powerpc/pseries Physical Attestation API
                            <mailto:linuxppc-dev>"

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Fixes: 43d869ac25f1 ("powerpc/pseries: Define papr_indices_io_block for papr-indices ioctls")
Fixes: 8aa9efc0be66 ("powerpc/pseries: Add papr-platform-dump character driver for dump retrieval")
Fixes: 86900ab620a4 ("powerpc/pseries: Add a char driver for physical-attestation RTAS")
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Closes: https://lore.kernel.org/linux-next/20250429181707.7848912b@canb.auug.org.au/
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250430022847.1118093-1-haren@linux.ibm.com