ionic: use int type for err in ionic_get_module_eeprom_by_page

ionic: use int type for err in ionic_get_module_eeprom_by_page

The variable 'err' is declared as u32, but it is used to store
negative error codes such as -EINVAL.

Changing the type of 'err' to int ensures proper representation of
negative error codes and aligns with standard kernel error handling
conventions.

Also, there is no need to initialize 'err' since it is always set
before being used.

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Shannon Nelson <sln@onemain.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Link: https://patch.msgid.link/20250912141426.3922545-1-alok.a.tiwari@oracle.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>