sparc32: fix sparse warnings in sun4m_irq.c and sun4d_irq.c

Fix following warnings:

sun4m_irq.c:308:6: warning: symbol 'sun4m_nmi' was not declared. Should it be static?
sun4m_irq.c:396:28: warning: incorrect type in assignment (different address spaces)
sun4m_irq.c:396:28:    expected unsigned int volatile *extern [addressable] [toplevel] master_l10_counter
sun4d_irq.c:469:28: warning: incorrect type in assignment (different address spaces)
sun4d_irq.c:469:28:    expected unsigned int volatile *extern [addressable] [toplevel] master_l10_counter

master_l10_counter is a pointer to __iomem - add annotations.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>