olpc_battery: Fix section mismatch noise

This patch fixes the following noise (by renaming _drv to _driver):

WARNING: drivers/power/olpc_battery.o(.data+0x100): Section mismatch in reference from the variable olpc_battery_drv to the function .devinit.text:olpc_battery_probe()
The variable olpc_battery_drv references
the function __devinit olpc_battery_probe()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: drivers/power/olpc_battery.o(.data+0x104): Section mismatch in reference from the variable olpc_battery_drv to the function .devexit.text:olpc_battery_remove()
The variable olpc_battery_drv references
the function __devexit olpc_battery_remove()
If the reference is valid then annotate the
variable with __exit* (see linux/init.h) or name the variable:
*driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

WARNING: drivers/power/olpc_battery.o(.data+0x128): Section mismatch in reference from the variable olpc_battery_drv to the variable .devinit.rodata:olpc_battery_ids
The variable olpc_battery_drv references
the variable __devinitconst olpc_battery_ids
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>