sparc32: Fix section mismatch in leon_pci_grpci

Passing a datastructre marked _initconst to platform_driver_register()
is wrong. Drop the __initconst notation.

This fixes the following warnings:

WARNING: modpost: vmlinux: section mismatch in reference: grpci1_of_driver+0x30 (section: .data) -> grpci1_of_match (section: .init.rodata)
WARNING: modpost: vmlinux: section mismatch in reference: grpci2_of_driver+0x30 (section: .data) -> grpci2_of_match (section: .init.rodata)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andreas Larsson <andreas@gaisler.com>
Fixes: 4154bb82 ("sparc: leon: grpci1: constify of_device_id")
Fixes: 03949b1c

 ("sparc: leon: grpci2: constify of_device_id")
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Tested-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Link: https://lore.kernel.org/r/20240224-sam-fix-sparc32-all-builds-v2-7-1f186603c5c4@ravnborg.org